Originally Posted by LordTrilobite
Though if this is true, then the question is, how do Guybrush and LeChuck travel in time?
I would have thought this was obvious: The treasure of Big Whoop/the underground tunnels.
I for one LOVE this time travel theory. Here's my assortment of ideas.
The voodoo lady knows what Big Whoop is and that Guybrush is from the future, as she can foresee the future. She knows he doesn't belong, so instructs him to find Big Whoop, to send.
LeChuck (as Chuckie) followed Guybrush through the tunnels because his parents sent him to find Guybrush. He came out in the past as an adult, before Guybrush got there. Unlike Guybrush, he initially doesn't want to be a pirate, but then realises the power he could gain from it, and he becomes the most dreaded pirate on the seas.
Guybrush suffers memory loss as a result of going back in time, but LeChuck doesn't. Ironically, LeChuck acts more piratey than Guybrush.
When Guybrush is killing zombie LeChuck, LeChuck gives up his charade to save his own life, and then remembers his parents' instructions, to find Guybrush.
The original expedition that found Big Whoop, the portal to the future, realised the implications of their discovery, and that's why they didn't want anyone to know about it, tearing up the map.
Guybrush makes references to modern ideas that other pirates don't understand, and he doesn't know where these ideas came from, eg. "I don't know why I said that".
In a way, the e-ticket sort of is Big Whoop, as it is a link to the future.
Guybrush can't drink grog in the first game, because he had been a kid, and had never drunk it before.
There are probably more connections I can think of...