Off-road training?

So, since getting an M-class endorsement to ride in MD 3 years ago, I've put about 20k miles on my 1997 BMW R1100RS road bike.

I've not ridden offroad in many years, and only then on mountain bikes. So while I know about feathering and trail braking, weighting the outside pegs on off-camber trails, and the joys of the endo (demonstrated here), gaining some offroad training before the ride will be critical.

Unfortuantely, off-road training centers are hard to find. BMW has one of the few schools on the East Coast. There aren't many other options.

And then there's the question of what to use to learn to ride offroad. Over the Xmas break, I developed a respectable addiction to checking eBay listings for second/third hand, dual-purpose, 450 - 650cc BMWs, KTMs, Hondas, Kawis, Suzukis, or Yamahas. I mean, I'll need to practice on something, right? Cripes, here it comes again -- the euphoria, the sweats, the shakes. Must ... change...topic....