A lot depends on what your expectations are of the solar panels. I have looked a lot into adding solar panels for my Roadtrek and also what the panels from the factory on the new Roadtreks will do. They will keep your batteries charged when you are not using the RV and they will be fully charged when you need them. They will not run the A/C. What you get out of use with them depends on if you are draining the batteries faster than the solar panels can charge them. If having a fully charged battery when you need it is something that appeals to you (it does to me) then go for the Roadtrek with built on solar. Adding them on later is expensive.