I think it all depends on what you are going to be using for electricity when you are there. If you will just be using lights "sparingly', and the water pump "sparingly", you might get by. If you will be needing to run the furnace very much that's a different story. The furnace fan takes a lot of amps.
Another thing is what have you got for a battery bank? You will have your best results from at least two 6 volt deep cycle batteries. Call harbor freight and ask them what all comes with that set up, and if you need anything else for it. I'm not sure if it needs a charge controller or not.
I have a 135 watt panel on the roof and a charge controller panel mounted inside the camper, and two T105 6 volt Trojans. There are times I wished I had another panel on the roof and more batteries.
2008 Cruiser CF26RK
2013 Ford Eco-Boost
Heavy duty payload - Max tow