I have Prophecy, my cousin has Factions

Ok, I bought an account from somebody (since I'm cheap and can't afford the game) and it was only a Prophecy account since I can't play Factions campaign, my cousin wanted to play too but only bought Factions so he can't start a Prophecy character. Will we be able to play together at some point?

yea when one of you buy the other campaign or yall cna pvp thats just about it

there's so way to travel between cantha and tyria? (or whatever the names are)

Like Cmoo said, you both have to buy both games if you wish to play with each other through the missions. However, like Cmoo said once again, you have the ability to play with each in the Player vs. Player area known as the Battle Isles. Once you get to Lion's Arch, and he gets to Kaineng City I believe, you both can go to the Battle Isles and play together against other people.

if one of you buys both chapters the one who has both can come to visit the other but only in that persons home chapter.

example

your cousin gets chapter 1and 2 he can visit/play with you in chapter 1( since he has both) but you are still locked out of Cantha and cant visit him over in Cantha

You can visit each other in your guild hall.

You can both visit on Battle Isles and play PVP together, which used to be the core of what guild wars was all about, I don't know if it's still the main point of the game anymore.

You can both AB together, go to guild hall together and everywhere that a pvp character can go.

Tell your friend to buy prophecies.

You can only do alliance battles if you have factions.