I live in a small town in Okla. and my goals with the solar is just for a back up and to run my shop lights and heaters to save a little money on my electric bill.
Please
get a good estimate in kWh for your back up loads.
Even combustion heaters with a blower motor can be a bit of energy and can get pricey.
Combustion generators are so cheap you don't notice the difference, but with the two small systems I built, I have found that
"solar generator" and batteries are easily 50 times the price of an equivalent off the shelf combustion generator.
Next is establishing how you're going to run these
critical loads and removing these loads to a separate panel can get pricey.
Another way is running these loads off an
extension cord, but that is a bit sloppy and some of these might not be plugged into the wall and have their own circuit breaker. Without the critical loads panel, won't be able to power stuff in an outage and when the grid is good sell electricty back.
Another thing I'm trying to figure out is something like a Victron than could do
load sharing and pulling from the grid, but can't sell back. Perhaps this could provide power for loads. Seems like an easy thing and I'm surprised it's not more popular, but its not that popular. If it even sends back a few hundred Wh of power, could trigger a something at the power company about an unpermitted build. For my area, selling the excess back or using the excess makes sense.
A
dual fuel or conversion kit for your generator is probably a much more rational and money saving solution, but there is something to be said about the independence a solar build will get you.
I can see this costing you anywhere from a few hundred up to $30k depending on what you want.
