Personally I would also try to minimise the rear overhang for fear of tearing it off offroad. For that reason I would not bother with side entry. A lot of people on this forum tow and a lot take their trucks offroad and get them very dirty, and most of them have standard rear entry campers.
Another consideration is that currently pop-up campers have rear entry and that design gets used and tested a lot offroad. Having a side entry one is likely to be a bit experimental - so there could be a risk that you get a structural problem because yours would be in effect a prototype.
If you want to get an idea of what those of us who take our campers offroad use (both hard side and pop-up) have a look at the Trip Reports sticky and search for "XTC" (extreme truck camping) to see what various forum members drive and where they take them.
Good luck with your choice,
Steve.
