My friend lives full time in his small camper and loves it. I asked him what he decided on for his power source. He told me he was planning on a battery and solar panel to charge it.
Turns out he ended up buying a Goal Zero Yeti 400 Solar Generator from REI for $460. I'm pretty sure he bought the Goal Zero Boulder 30 Solar panel as well, which is $200. All because of the easy and simplicity offered in a single package.
He's effectively purchased a 33amp hour battery with a charge controller and inverter built in, and a 30 watt solar panel. For $640.
Meanwhile, I'm tackling the same task for our pop top camper on our truck. I bought a 125amp hour batter for $120. (4 times larger at roughly 1/4 the price.
I sourced a kit on Amazon for a 100w solar panel complete with charge controller, wiring and brackets (from Renogy), for $200. That the same price as the GoalZero panel, but 3 time the output, and includes mounting brackets.
For less than half of the goal zero system price, I'v managed to create a system 4 times larger, faster charging, and more versatile.
I've offered to help him do the same. We'll see!