Regarding "Spinal Back Pain Issues", I feel the biggest factor will be the design & quality of the front seats and also the cabin furniture. The secondary matter over the quality of the ride will be best in a Sprinter, then a GM, and finally a Ford. All RV manufactures install aftermarket seats and they vary a lot. If your wife has a problem with the seats, plan on replacing them with a better quality, fully adjustable design. Fully adjustable should include lumbar, a high priority for you. To get such seats from the start, you'll need to be looking at higher-end brands.
Upon request, some manufactures will install the same front captain seats inside the cabin. So if the fronts are working, the cabin furniture will also work. I've seen this applied in the brand we own,
Phoenix Cruiser. You simply ask Phoenix to install two additional captain seats (and a small pull-out table) identical to the captain seats up front, instead of the typical convertible couch/bed. It is not a popular request, but I see it now and then. It actually works better without a slide because of the additional wall space to work with.
CLICK HERE to see the seat supplier for Phoenix Cruiser seating. You can buy direct from them. As I mentioned before, you will want lumbar adjustability.
