Why do DP's typically have the door in the front and gas MH's have the door in the middle?? It seems like there could be more floor plan options if the door was moved around.
Gassers typically have the engine in the front thus have a doghouse that would make a front door option a problem. DP's obviously don't have this problem so they can have a front door. I personally think this is a carry over from originally being based on busses and some still are.