Thanks so much to all, I can see I chose the right forum. Your cruise/electric tips sound good, it will be fun to play around with it. Solar is just because the sun is free, and the panels don't cost too much. Sitting in a parking lot all day should amount to something. Otherwise, plugging into home is on the menu, especially now that there are so many offers to go solar at home, too!
I'm curious about the parallel setup, will have to give the physics a look. Gas motor only thru the electric requires the electric to be locked? Maybe no problem, the electric motor may be solid, input shaft to output shaft. Gas motor and the electric, the electric is going to act like overdrive, add to the motor rpms and torque. Electric only will try to turn the tranny backwards? I know it's all been done, so the answers are out there.
My first need is finding good deals on electric packages and good match-ups of electric motors and trucks.
I saw the Azure setup had two driveshafts, probably to protect the tranny's tailshaft bearing, which isn't engineered for the weight of an electric motor hanging out there, wringing around. Trannys always wiggle around a bit, and a separate driveshaft to the electric motor solidly mounted is probably wise. Those splines and u-joints forgive a lot. The second driveshaft from the electric motor to the rear end just has to be long enough to do it's job, allow the rear end to do it's thing.
So, the first thing is finding a good match-up of truck and electric drive. Any help is appreciated. And, PS, I plan to have solar film on roof, hood, and camper top.