Good luck.
Like I said, just buy the generator, and thank me later. Your not retiring on profits from a solar system,unless you have a few hundred acres of land to cover in panels, and even then, you lose the value of your otherwise useful land, so its not a good way to use solar.
Sure you can invest 20+ grand into a solar system to get off the grid, but you have to replace it again in +/- 10 years, so your just throwing money away that can fuel your generator, that will still be running like the day you bought it 10 years ago.
Solar just hasn't come far enough yet, or everyone would be doing it.
S.