PTP:
If you haven't bought some, here is a cheap way to make some wheels. They work GREAT on sand and flat surface, just not to good on uneven ground. Under $100 without cradles and under $200 with (unless you can make your own cradels).
http://www.geocities.com/mec_coleman/tip13.htmDoug
dsnell4 at houston dot rr dot com