As for the weather making a difference in your fridge it will take longer to cool down on a hot humid day. If anyone has opened the door they warm up fast when the door is opened and it takes them a while to cool back down again.
Yes, after messing with it for a while now, I think that's pretty accurate. I've more/less let the fridge run nonstop for the last several days. When the AC in the trailer is on, no problem. When I turn it off and it gets hot inside, the fridge can't keep up.
Regarding the mattresses, of course a standard size mattress won't fit the bunks :S. They measure 32x74/75. I've done some research, at it appears that this size isn't too uncommon for RV's. But naturally, that just drives the price up. I just not paying $300+ per mattress for the bunks! Fortunately, I've found a foam mattress supplier that has a twin size for around $100 each (fries shipping), that is 6"' but I'll have to cut down the width. Add some accessories to it, like a mattress cover, and it gets up to about $150. Unless anyone has any better ideas, I'm going to pull the trigger on those. FWIW, the full size bed appears to be the standard size, so that'll, be easy.