We sometimes run tarmac buggy at our local parking lot races. (called the 'FastCats Depot')
http://www.youtube.com/watch?v=bv2Iri1CmDE
Unfortunately this isn't a dedicated offroad track... it`s an onroad track us offroaders run on just to get our buggy fix. That explains the dinky little jumps.
The best tires by far to run are worn down dirt tires (hole shots, bar codes, block heads etc) with something like Buggy Grip applied to the tires. While dirt hawgs last longer than the offroad tires, the traction sucks by comparison. An old set of hole shots might last you a few weeks of racing. None of us bought any tires, we just used tires that were too worn out to use on dirt any more.
Also, the track is blown off with a tennis court blower, then sprayed with sugar water to make the traction extra good.
A track with proper jumps, like the one`s shown above, would be awesome!