Generators in fivers add a lot of weight to the nose for very little return. A portable Genny like a Honda 2000 watt is pretty cheap compared to built ins.
I would tell you floor plan is Paramount. The bitterness of a lousy floor plan will far outweigh the thrill of a small size. Find what your comfortable living in. All else is irrelivant.
Please forget 2500 series trucks. By the time you load it with bodies and stuff your available payload is just too lacking. Besides you can get a comparable 3500SRW for nearly the same money. To me it's a no brainier.