i would seriously consider taking out the generator, make that space into battery bank, and throw up as many solar panels on the roof as you can afford.
i love my big ass gen because i can power my full size kitchen stove and a pair of A/C units all at the same time. a 3500w would not cut it.
i'm all diesel and electric. if you're going to add another fuel, i'd add propane for a stove/heat.
my electric needs outside the stove and the ac are all 12v, with the exception of my computer, monitor and tv. they run off a 300w inverter. my 400AH battery bank easily handles that as long as i run the generator 6-8 hours a day.
if my gen didnt work, i'd go solar.
the number of hours on your gen is pretty high. double mine and my bookmobile is a '93.
the only 240v appliances my bookmobile came with were 3 crude electric heaters.