I bought one of these from Amazon three years ago:
https://www.amazon.com/Renogy-Watts-Volts-Monocrystalline-Solar/dp/B009Z6CW7O/ref=sr_1_6?ie=UTF8&qid=1525820541&sr=8-6&keywords=renogy+100+watt+solar+panel+kit&dpID=41rOZxjogoL&preST=_SY300_QL70_&dpSrc=srch
I also bought a little 30 amp controller, some z mounting brackets & hook up wire, all from Amazon. I put the panel on top of my Phoenix Cruiser and it worked amazingly well. I couldn't have been more pleased but the next year I added another 100 watts on top as well. Now we can boondock for unlimited time and really keep our batteries well charged. We have two six volt golf cart batteries. This may be the best mod I have made to a RV.
Paul