Don't know if I did something wrong, but I have infinite loading issue in Clyde's fortress. When I got there for the first time everything was OK, then I got down, walked around for a while and tried to get back. It didn't wotk and turned into an infinite loading. Buddy swap doesn't help. Any previous saves in this location don't work neither. 

I have the same problem. Did you solved it? Anyone know how to do?

YES! Same exact issue, have PS3 disc version and can't get past the battle with Clyde.  After I defeat Clyde, the screen goes to black "load" screen, and that's it.  They need to patch this now.

It seems like everyone has this issue. I believe it has something to do with Cartman. Try using Butters in the Craig battle and you shouldn't have a problem loading afterwards.

Yeap, Playing other Character than Cartman Helped :] I finished main Quests. Just left some ni-story quests :]