id suggest planning a plan B for when this doesnt work out. That said figure out your power usage and we will help you size accordingly. Id be looking at 3-500 watts solar and a bank of as many 6V batteries as i could afford (hopefully 8). you dont need 4 seasons, follow the season you want. winter where its warm summer where its cool. forget milage, its bad, its not going to get better.
dont be cheap with your charge controller
once you start to be ok with the bad fuel milage add in that you should expect to burn some propane
keep an eye on weights make sure you dont run out of payload.
next up water. figure out your plan for potable, black and gray water and let us know so we can help
