I just got back from a decidedly illuminating ride on the Greenway, due to the fact that I got fed up with trying to patch a tube that won't stay patched. The recent industrial-strength mowage has revealed any number of four-wheeler trails of which I was previously unaware. With a little work, I was able to ride the full length of the Greenway from downtown to where the houses get really big and expensive without riding on pavement all that much.
Since I've been thinking about the available space nearby for MTB trails, I was keeping an eye out, and I think there may be an opportunity here for some nice, pure (read: too narrow/twisty for ATVs) singletrack between the bike path and the river. It wouldn't all be in the trees, but I'm impressed at how much space is in there. I don't think it would be too much effort to clean out the four-wheeler sections just a bit (mostly the burdock is leaning into the trail and the stumps aren't cut low enough) and to build some tight, possibly rather technical singletrack.
The length of this area is around five miles, say half of that is in the trees and three quarters is quite separate from the bike path. I rode somewhere around 12 miles today, which I think is pretty decent. Since the whole area is pretty flat (nowhere near the elevation change at TR), what could set the MTB trails apart could be their technical aspects: tight corners, rock gardens (which may have to be handbuilt over time), and maybe even a few obstacles/bridges made of some of the junk out there (there's a refrigerator I can see getting some use). The only exception to this would be the extreme south end (by the police line tape and the paintball course, if you know the area), which is pretty wide open under the trees.
Additionally, flatter trails could be advantageous during the winter. I know I would ride some decent trails just to keep from going nutso on the rollers, and maybe a future winter MTB race couldn't be discounted...
I'm going to try to make up some maps, at least of the existing trails, depending on whether I can borrow a GPS unit or not. I'm no trail planner, but I think there are ways to make this work (and keep the trails accessible to bikers/runners and keep the ATVs /snowmachines out). If anyone's interested in getting together for a couple hours a week to clip/build/design, let me know. I think that with a little effort and some hard use to wear them in (go ride!) over the next few months, we could have some decent, rideable terrain right here in town.