I have used and now use both solar and a generator.
Due to my camping style, im in the woods under thick trees most of the time, so the generator gets the most use. My solar is not mounted to my rv, its free standing but i still have a difficult time finding and following sunny spots throughout the day.
Generator use in NP's usually have hour restrictions regulated by individual parks.
You might find it easier to lift and move a 46 lb. 2000 watt generator like a honda 2000 that can be paired to an additional unit giving you a total of 4000 watts. Otherwise a 3000 watt might be in the 100 lb range. If you can manage the weight, go for one single unit.
IF not......
You would use only one 2000 watt generator until you needed to run your a/c. A 13,500 A/C will probably need more than 2000 watts to get it going unless you install a hard start capacitor on the RV a/c unit.
http://www.modmyrv.com/2009/05/27/rv-air-conditioner-hard-start-capacitor
