I just went riding at a private park this weekend near Montrose. It is open to the public on Saturdays for 10 bucks you can ride. There are over 400 acres to ride on.
They have a small mx practice track but it is mainly trail riding.
If you have a 4x4 this is a great place to go. There are alot of hills but some of them are rutted pretty bad.
I could have rode the place on my 250r but I think a 4x4 is the way to go. Even if you don't have a 4x4 though it's worth checking out if you like hilly trails. Just make sure you got a good skid plate .
There is a small creek that runs through the place that is fun to ride also. The phone number is 1 800 368 2604 . You can become a memeber for 100 bucks a year and get a key to get in anytime.