Small world - a family friend owns Mueller's Auto Recycling in Altoona. He didn't have any vintage 454s for my rig, though. He only has newer stuff.
Anyway, the way the engines are installed in motorhomes does not allow for great air circulation, but by '92 Chevy had all but solved the overheating issues that seemed to plague them in the 80s. If yours overheated in what must have been 50-60 degree weather it wouldn't have much to do with air circulation. Something went wrong.
Do you have a driver's side door? If so, engine R&R isn't too bad. If not that makes things exponentially more difficult. It does not appear as if you can get the engine out the front of that thing. Maybe he bottom, but more likely down the hall and out the door. Not a pleasant proposition.
1984 Allegro M-31 (Dead Metal)