I figure you're missing out on a lot of fun if you don't PvP, though.

Meh, not me. Other people are jerks, I much prefer to play largely by myself.

I might do some pvp, I'm just wondering if it would be a good game for Raiha and I to coop on. How many hours is the campaign?

Plenty, and then there's bonus dungeons and stuff, and you can go back and do hard mode, or vanquish.

Well let me put it this way.

Campaign can be finish in a matter of hours if you neglect to do the bonuses and you're just after either the storyline or the end-game content of that campaign.

And yes, having another player to play with helps a lot. There are some parts in the campaign where you'll definitely need someone to help you out, like if you're a warrior and carry a bundle item, it's hard to drop it and fight then pick it up again the said item, but with another player, preferably a caster, can carry that for you while you just wade in and fight (assume your main character is a warrior).

If what you're after is just the storyline, start with Prophecies > Factions > Nightfall then EoTN in that order.

Hope that helps!

In terms of actual quality Nightfall is better than Factions is better than Prophecies though.

qft sadly...

edit: Nowadays it's either NF or Factions first followed by EoTN then finish NF, Factions and Proph.

I'd play more GW if I pvped more. I absolutely loathed the PvE on basically every level.