Systems are pretty inexpensive and pretty easy to install.
This is a newer version of what I installed a few months ago adding a 5th panel for 500 watts.
https://www.amazon.com/Renogy-Monocrystalline-Starter-Charge-Controller/dp/B06X1FV5N2/ref=sr_1_1?ie=UTF8&qid=1495157724&sr=8-1&keywords=renogy+400+watt+solar+panel+kit+mppt
400 watts would have been enough but check to see what your roof configuration will allow.They also have 200 watt kits that are cheaper. The kit comes with most of what you need but I like to add isolation fuses between battery/controller/panels and a on/off switch between the battery bank and the camper.
As far as installing on the roof I am not sure but there must be a way, I have sen them on NL campers more than once. Fiberglass can be drilled with the right bit.
We removed our generator, added 2 golf cart batteries in it's place and have been running on solar now for 8 months (almost) full time.