Solar, like horsepower, gas mileage etc. tends to get quite over rated as to output/capability. It's great in that it's quiet, convenient when the sun shines, and requires virtually no maintenance other that what you would already doing with your batteries, and of course cleaning the panels occasionally. It's not necessarily cheap however, doesn't work when parked in a nice shady spot, rainy or cloudy days etc so you will still need a generator, or other source of power in most of the sort of areas I like to camp.
Since you appear to be new to RV's, first you'll need to figure out how much power you'll need to do the sort of stuff you like doing. Reading books by LED light, minimal power usage. Watching 46 inch flatscreen tv with propane refrigerator running, couple lights etc. and my 5er is drawing 10 to 12 amps. Add in it's cold outside and the furnace is running a fair bit while the days are short, and tend to be cloudy and you'll need a lot of solar on the roof to have a chance of keeping your batteries up. Determine need, or detailed desires first and we can provide much better situation based advise. Include activities, type of RV, and locations where you plan to be, stuff like that will help a lot.