David, I have 2 90 watt solar panels on my rig. They charge 2 6 volt trojan batteries. I dry camp 5-6 weeks in a roweach year. And with the occasional help from a portable generator I have always been able to keep my batteries 50% or more charged. I run all the essentials in the rig as well as a 32" flat panel in the living room and a 20" in the bedroom with an inverter. TV time is usually about 2-3 hours per day.
Determining how much solar panel you need will depend on what you want to power up when dry camping. The installation is pretty simple. You need the panel or panels, plus wire, a fuse,and a charge controller. The controller is needed to control the charge to your panels and most have displays that show you voltage and amps. The controllers run from less than a hundred bucks to about $200. The size you need will depend on the number ofamps yourpanels put out.
There are several places that specialize in RV solar systems. There a couple of good ones in Arizona around Phoenix if I recall. You can google RV solar systems, Some of their sites give you a lot of info on how to set up a system and how to figure out how much panel you need. I have had mine for 12 years and they still work great. Price hasn't changed much in that time.
If you need more info on those solar places, let me know and I will look them up.