Also condsider a DirtSurfer:
they take up less room in your car than a buggy
they have brakes
you don't get a sore back
they feel a lot like a kite board to ride
they're awesome fun downhill when there's no wind too
very stable once you're moving
Checkout
dirtsurfer.com/ - there's a new use for your old windsurfing sail that you never use anymore :-)