It was actually an eye opener for me when a few months ago we went to a rather large RV Show sponsored by a couuple of the largest SOCALIF dealers. We parked on 4 story parking structure, and looked down over the assembly of assorted Motorized and Towable Rv's.
I was astonished how many of the Toy Hauler TT's and Toy Hauler 5ers had single battery maintenance type solar chargers on the roofs, and a smattering of then had up to 4 panels! And the Class A's were also in many cases topped by at least a single panel, the big luxo buses were well equipped with multi-panel systems.
Next time when you go into an RV, it seems that the roof panel charger panel controls are often in the master bed rooms on the Trailers as well as the bigger C's and A's. Or located on the master power panel.
Yeah they are an expensive option...but how many things on a RV will pay for itself?