Updating alternator - have a few questions

You'd be way ahead, I think, to buy a stand alone generator for the trailer's heat and stove. They make them in many sizes now. Electrically speaking, it makes no sense to have to fire up your hot rod to make breakfast. Or,who's getting up in the middle of a cold night to fire it up, so you can be roasty-toasty.
The running lighting would be an add-on to your cars system.
The big alternators are not cheap, and when they are working hard, they are putting out more heat than watts. Nearly ten times as much, to my recollection. That can't be good for them.You may as well park the car with the nose under your bed on those cold nights, and crack the hood open.heehee.