I suggest that you make sure you're concerns about a longer DP are truly valid. With the number of people you mentioned it would seem that the longer the better. As far as campgrounds go, that seems to be an opinion that some folks tout with little basis in fact. It would seem to me that comfort trumps the occasional park with a length restriction.
And, you are totally correct in you assessment of the rear engine and the driving pleasure...it's a wonderful way to travel. Downside is you hear every pot and pan rattle, window squeak, and etc.