I've played with all the expansions which come in the Big Box (Princess & Dragon, Builders & Traders, The Tower, Inns & Cathedrals, and The River). I might have done it all with The River 2 as well, but I'm not sure.
I haven't played Carc in a while, but usually when I do now I just use the base game (with the big meeples). It goes faster and you don't miss out on very much.
One cool thing about Carc, though, is that the game time is almost entirely dependent on the amount of expansions used. Since the game lasts for X pulls, it plays in the same amount of time with 2 players or 6.