Confining the heat or cool air to the cab area generally sounds like a good idea and years ago I did just that. But now I want the rest of the coach to be warm in winter or cool in summer when I get where I'm going so I do run the generator to run A/C whne going down the highway so the coach will be cool in the summer. The A/C will not adequately take out the heat in our unit if it is hot inside and 90 plus outside. In the winter the furnace will take the chill out reasonably fast. Good idea but not for me.
Bob, Sandi & Marmaduke the Big Pug
SW OREGON 2004 Journey 39K, 330 Cat
If towing: a 2006 Mini Cooper or 1995 Wrangler