The Timeline

Date Events
In The Beginning…
T-35 Yrs Robert Ford and Arnold Weber begin work on what would become Westworld. We might assume Robert and Arnold had already done some work in robotics and had some idea of what they wanted to do. In fact, it seems very much like a start-up idea conceived by people already in the business, but seeing an unfilled niche they could capitalize on.
T-34 Yrs The hosts "passed the Turning test after one year," according to what Ford tells Bernard.
(2 Yrs) Dolores begins to impress Arnold (who's suffering from the loss of this son). It's possible Arnold becomes a bit too enamored, or at least very caught up, with her.
After failing with the pyramid metaphor, Arnold conceives of The Maze.
Akecheta and Angela bring Logan to a private party filled with hosts. (Note that William is around and dating Logan's sister!) Logan sleeps with Angela (and other hosts). Arnold brings Dolores to his (under construction) home.

Delos invests in Westworld.
Dolores solves Arnold's maze, or at least convinces him that she's alive and, therefore, the park must not open.
Arnold fails to convince Robert to not open the park. Arnold adds the Wyatt character to Dolores, who (along with Teddy) kills all the hosts. Dolores kills Arnold ("These violent delights have violent ends"), then Teddy, and finally herself.

Ford repairs the hosts and suppresses Arnold's suicide.
T-32 Yrs The Park Opens. (But it "hemorrhages" money.)
(2 Yrs) Logan visits multiple times.
Logan's sister visits for her bachelorette party.
30 Years Ago…
T-30 Yrs
Day 1
Logan brings (brother-in-law to-be) William to Westworld.

They arrive from the mainland on the monorail.

Hosts greet them as they exit the train. William meets Angela, who probes him a bit (probably just banter, as the park would likely have his records already). She takes him to Garb and Gear (and Hats).

William and Logan take the train to Sweetwater. William bumps into the Grizzly Adams character and helps an old prospector out of the mud.

That night they have dinner, but are accosted by the old prospector, who gets forked by Logan. They go to the Mariposa for hookers. William (just) talks to his (Clementine). [S01E02]
T-30 Yrs
Day 2
William wanders around Sweetwater, gets involved in a shootout with a villain, and saves Clementine. He kinda liked shooting the bad guy, so he decides he will go bounty hunting with Holden.

As they prepare their horses, he sees Dolores drop her milk can, which he picks up. They talk, but Logan pulls him back to their preparations.

That night, in their camp, Dolores stumbles in and collapses in his arms.
T-30 Yrs
Day 3
They pass through Las Mudas, and Dolores encounters Lawrence's daughter (who knows about maze). A sheriff tries to take control of Dolores (who is off her loop), but William intercedes ("she's with me").

That night, in camp, William and Dolores talk. Dolores seems to be having visions here. Or maybe it's the Dolores from timeline 2 (or even timeline 0). Or maybe it's all of them.
T-30 Yrs
Day 4
Dolores waits outside as the men invade a farmhouse where Slim and other bandits are holed up. They capture Slim. Logan gets a better gun.

When Logan hears Slim mention El Lazo, he shoots Holden, so they can pursue the "best ride in the park," a black hat path with El Lazo.

They head to Pariah. Once there, Logan tells William a little about the park and its struggles. They apparently arrange to stay the night.

Dolores (at least a Dolores) has visions while in the graveyard outside the town as well as that night after seeing dead bodies in coffins. She also has a vision of herself in the Parade of the Dead.
T-30 Yrs
Day 5
Logan, William, and Dolores, meet El Lazo.

Dolores has a flashback that moves her to speak to El Lazo and thus secure their place with him. (Perhaps a part of the maze Arnold created?) El Lazo assigns them the task of heisting the nitro from the army.

Which they do. William kills three of them (Slim kills the fourth).

They return with the nitro to Pariah, and El Lazo invites them to an orgy that evening.

That night, at the orgy, William and Logan have words, and Dolores has another vision of herself as a fortune-teller. (She talks to herself. She sees the maze on Tarot cards. She plucks at something in her arm; unravels.)

El Lazo's trick with the nitro is discovered by the Confederados. Logan is taken. William and Dolores flee (with El Lazo) on the train, but not before Dolores goes badass and shoots three.
T-30 Yrs
Day 6
William and Dolores (and El Lazo) ride the train through Ghost Nation territory.

William and Dolores talk. They do more than talk…

Later that day (or next?), Dolores draws a scene she imagines (but finds later). The train is stopped by boulders on the tracks; it's an ambush by the Confederados.

El Lazo sends out nitro-filled Slim to explode, and they try to escape on horseback. The army chases. Ghost Nation natives show up, which allows El Lazo, William, and Dolores, to escape.

William and Dolores part ways with El Lazo. They find a river with dead soldiers (Confederados) who planned to ambush them (but were killed by Ghost Nation Indians).

William probably kills the one they find alive. They continue and eventually find Escalante, but it's buried under sand. (This may have been done after the massacre Arnold started.)

Dolores is getting very confused. She's not sure when she is. William leads her away from the buried town.

That night they encounter Logan and his soldiers on the road.
T-30 Yrs
Day 7
Soldiers Camp. Logan has William and Dolores captive.

It's day when Logan takes Dolores away, but night when he returns. She seems fully dressed, so it's not entirely clear how the entire day passed for her.

That night Logan gives William the picture of Juliet. He also stabs Dolores to show William her machinery. Dolores manages to escape (after slicing Logan and shooting some soldiers). William reconciles with Logan, and they drink. Heavily.
T-30 Yrs
Day 8
Soldiers Camp. Logan wakes from the party…

William has embraced the dark side and killed every host in camp. With a big MiB knife. Logan is going to be his prisoner to help him search for Dolores (and don't call me "Billy").

William (with Logan in tow) finds El Lazo. He needs help finding Dolores. They set upon a camp of soldiers, killing them all. William find the LeMat revolver.

William and Logan in Escalante (which is still buried). The picture slips out of William's gear and falls to the ground.

William and Logan at the edges of the park. William sends Logan (naked and tied) off on horseback. He finds a black hat he likes among the dead bodies (he presumably just made).
T-30 Yrs
Day ?
William returns to Sweetwater and see Dolores.

(Dolores probably died shortly after escaping the camp. Now she's been restored and set back on her loop. And possibly been rolled back if she showed signs of "breaching" or waking.)

William is devastated that it seems to have all been an illusion.
And Then…
(30 Yrs) William takes control of Delos from Logan and "saves" the park. He also goes on to marry fair Juliet.

The park, being in operation for 30 years, is successful. It's quite possible Delos merely subsidizes the park as a cover for its own project, which apparently involves gathering guest DNA and recording their experiences while in the park.

We can assume William visits the park frequently in the years that follow. It's not clear when, or if, his visits taper off, but that is the impression. His real life and family may have demanded more and more of his time.
(30 Yrs) ¶ Dolores loops as the rancher's daughter. The inherent suffering of the loop may serve as her punishment for the massacre, but certainly serves in leading her towards awareness.

We can assume she continues to make journeys seeking the center of the maze (she is while she's with William and probably does after).

¶ Maeve loops as a frontier woman with a daughter (husband unknown, let alone if it might be Hector). Her loop also includes suffering, assuming the attack by members of Ghost Nation happens regularly.

¶ Peter Abernathy started as a Shakespeare-quoting cult leader, but at some point becomes sheriff (we assume — could just be backstory), and finally Dolores' father.
T-15 Yrs
????
Ford begins work on Bernard. He's found the human engineers not up to the task of creating subtle emotions in the hosts.

One read is that he builds a host to continue Arnold's work, but that doesn't make much sense (like the Enterprise computer creating Moriarty). If Ford can make a robot to do certain work, he can do that work himself.

I think, instead, Bernard serves as a test-bed for Ford to experiment with subtle emotions in Bernard. This seems to come out in their discussion following Theresa's murder.
T-10 Yrs Bernard goes to work as Ford's assistant.

At one point, Bernard mentions he's been working there ten years.
Recently…
T-1 William's wife commits suicide.

After the funeral, due to what his daughter says to him, William goes to the park to kill Maeve and her daughter as an experiment. On the one hand, he feels nothing, but on the other, he sees Maeve come alive.

Ford and Bernard try to fix Maeve, but she's been badly damaged by seeing her daughter casually killed. She kills herself in front of Ford and Bernard.

Presumably her memory is wiped, and Lee Sizemore inherits her as a madam for the Mariposa. This ties in with Felix telling her that, despite her own memory, she's only been the madam for about a year.

¶ We might assume William goes back to the real world and wraps up his life, because he's declared he's "not going back." He plans to return to the park to search for the maze…
Modern Day…
T-0 Season One begins.