Twenty posts in <24hrs!
As a first approximation, I'd go for 1/3 hypermiling, 1/3 powertrain and 1/3 aerodynamics.
For the aero, fix the hood and dump the bug deflector. The airdam is fine, but add air curtains on each side. Your search term is '
edgarwit'. Seal the cab bed gap. Maybe a slab of magnetic stick-on car door sign material.
A compound-curve aerocap is best, but a half-tonneau is very close. You'd have the front half of the bed open and a trunk/toolbox/camp kitchen with a vertical tailgate.
For the hybrid drivetrain, consider that
20hp GM E-assist altermotor. It would need a controller and 55-72v battery pack, but that how you get serious regen.