I appreciate all the input!
I'd be speculating on wire size as I'm not home at the moment. I can give it a look when I get home and confirm...
The 30 amp fuse is what was in there new... After the first one popped I just simply replaced it with the exact same thing and didn't think much about it. Surely that's not a factory mistake or that'd be true on every camper like mine, right?
The first time it blew I was halfway through bringing the slide in. Yesterday it blew the instant I hit the switch to bring the slide out...
I'll update on that wire size when I get to the camper...