For the price of the expensive solar panels, you might as well just buy a larger battery.
The range to weight ratio is much better with battery then solar.
Easiest thing is like what I did.
Two motors, two light large batteries, regen and your good to go.
I'm pretty sure, if I can get 2 - 36v 30AH 30C Lipo and kept my speed at 17mph I could easily achieve 200m distance if I pedaled a little on the starts.