Tips on increasing range?
Light weight, eliminate every ounce you can.
Use regenerative braking, this not only increases your range, but saves wear and tear on the friction brakes and eliminates having to oversize the braking system due to extra weight.
Lithium-ion batteries, an expensive option but it will reduce the weight considerably.
Low drag coefficient, making it slippery to the wind does help!
Use low rolling resistance tires.
A/C conversions do get greater range, also, primarily due to the overall efficiency of the A/C motor.
And the #1 tip: Plan your trips! That way you don't need the range to start with!
Small windmills (of the size that would be easily portable), or even solar panels will not increase your range say more than 5-10 miles a day. You would be much better off having those in a stationary location and use them for daily charging.