As far as stopping and using the restroom, I totally get it. Although, you could put water in your fresh water tank, and use the restroom while on the road. Of course you still have to stop. I have stopped on the site of the road (not the freeway), because my DW had to go. Have also exited freeway and found a parking lot, or stopped on side of the road.
I would think if you can get a MH into a fast food area, you should be able to get the 5er in as well. Lots of fast food places on the road advertise bus parking.
It's all relative I suppose. I think the thing about MH's that worry me is if Im on the road, and ANYTHING major breaks with the drive train, I am out of sleeping accommodations. At least with a truck/trailer combo, if the truck takes a dump, I can live in the trailer til it's fixed, and not have to rent a hotel AND pay for the campground or place for the trailer. I suppose the likelihood is not great, but it's still there.
Anyways, good luck on whichever way you decide to go.
Mike