How long of a ride are you looking for? I have two ideas in mind (one of which I have permission to access, one of which is a state gamelands access road system), but together they will take only about three hours of riding total. And they're fairly tame.
This is an old video I took (part of me documenting the entire ride). Old logging roads circa 1880s-1920s, then lightly improved with Cats. Seven or so miles, but will take the better part of 1:00-1:30 to travel.
http://www.youtube.com/watch?v=AqukJF442vI
Only concerns for folks who care is that it gets tight with brush at times, so you may get a trail pinstripe or two, and if you go after rain, it's muddy (but you get to see great cascades from the mountain). Oh, and you need to come up to the Pokes to ride 'em.