Solar to me is not to save money on generator gas, which is a trivial cost. Solar is what lets us stay off grid many days/weeks in a row without having to find shore power to get the batteries back to working right from doing too many 50-90s in a row. (RJ doesn't have that problem, so his reasons for solar would be different) Solar costs quite a bit so you would have to run the gen a lot for battery charging instead to pay for the solar.
I don't know of a way to save on propane using solar/battery. Maybe with an electric blanket instead of the furnace so much, but not with a big electric heater instead of the furnace.
Propane is only a problem if it is difficult to get a refill where you are camping off-grid. Mex complains that it costs more for gas for his truck to go get the propane miles away than the bottle of propane itself costs ISTR.
Some seasonal (five month stay) campers at our summer campground arrange for a big propane tank next to their rigs and get propane delivery service for that. I find it is easy to just take a 30lb bottle to a garage for a refill every so often (costs about $29 usually)
Gas for the generator is also easy for me where the gen always stays in the back of the truck so I fill the gen when I fill the truck at a gas station. It all goes on the same bill and I don't even notice how much was for the gen out of that. Not much.
