Renton, permanent or semi-permanent setup like snowbirds is different from traveling. There are (usually) more needs, but there are (usually) less restrictions as to the battery size, panel tilt, wiring etc. You should tailor your solar to your particular situation and to your particular lifestyle. In sunny destinations in winter (say, October through April), a generator-free living is possible with flat solar anywhere from 300W. Some people can't make it with 900W, in the same location.
Do you know already what kind of RV-ing you are going to do?
Controller size and type depends on solar wattage and type. Up to 280W it's usually PWM controller and 12V panels in parallel, or one 24V 250W panel and MPPT controller. From 300W and on, it's 24V panels in either series or parallel, and MPPT controller of appropriate size.
Have you determined already how much solar wattage you need?
Battery bank and inverter size depend on number and wattage of 110V gadgets that you use.
Have you decided already what gadgets you are going to need?
