George,
I will take a stab at it and give you a short answer about the viability of solar on a typical shed. (10'x12' at most.)
It would take a very long time for the system to pay for itself. You still would have a problem running everything in the RV. Like AC. The frig is a hog if you run it on the batteries with the 110.
I do not know what State and location and the amount of sun you might get daily. That can be a factor also.
I am assuming you are not speaking in the terms of tying into the grid vs using batteries and an inverter.
I might direct you to this site to read in more detail about what you can expect from solar.
http://www.jackdanmayer.com/
You can install a system that you can use that would furnish you with enough power to run everything with a mindful eye on your consumption.
The answers to your questions can be long and drawn out and still not give you a definite answer because of the unknown situation you have as far as expectations and usage.
Joe