Solar panels, windmills and a shit ton of batteries is way out.
No, you take the fun out of all this.
Honestly? I'd look into mounting 2-3 extra Honda/Kia/$5 apiece at the pick-a-part alternators onto the D15 in question and using a bank of lead-acid batteries, you'd have close to 900+ watts steady state output and the batteries would soak up any sudden loads associated with current inrush when compressors turn on. If you're resourceful about this it could be cheaper than buying and driving a generator.
You'll probably have to drive a generator with the crank snout, if you go that route, but you already know this.
I'm not big on generator tech, I know spinning an inductor motor will generate electricity but I do not know how efficiently it does so - meaning, I'm pretty sure they are based off of inductor motors but if there are any inherent differences in the design or if it's all in current monitoring/smoothing/overload protection shit added on to a plain jane motor... bleh.