Depending on your roof space and what you find "on-sale" there are larger panels out there. We ended up with three - 250w panels on a barter. These fit up there but they eat up the real estate quickly.
As for batteries we went with AGMs because these are in our cargo box which is accessible from inside. AGMs are sealed and do not require ventilation. In order to keep the wiring under control the batteries are very close to the charge controller (Schneider Electric, another barter item) and all that taps into the coach without long wire runs.
We purchased additional 12v outlets and have them wired in the back room where our desks are. We went online and purchased 12v power adapters for our computers, scanner and printer and my camera battery charger.
My girlfriend being an Electrical Engineer has this thing wired tight and well over-designed. The good news is that panels are out there on the used market as well as the rest of the equipment needed to get up and running. We're currently trying to barter for a new Outback inverter. Inverters are everywhere but true sine wave inverters seem to be a little more difficult to obtain for "free".
Get an idea of what you would like and then start looking around at what's available. It'll all come together nicely.