running outa money

I can understand your apprehension to taking kids out on trails. You don't need to write off national forest riding because of that though. There are plenty of dirt roads in national forest just outside of Denver that are open to dirt biking so long as bikes have trail passes and spark arrestors. The national forest surrounding Winter Park Colorado and hour and half west and north of Denver via I70 and Hwy 40 is one such area. Plenty of gravel fire roads that any vehicle can ride on are in that area.

You would need to consider things like making sure your kids understand and can abide by basic traffic guidelines like staying on the right side of the road, not hogging corners and riding in a reasonably safe and sound manner. These roads are open to every vehicle pretty much including bicycles, atvs, side by sides, cars, trucks, ect. as well as hikers, runners and dogs off leash are common too. If your kids are so young and inexperienced that they would have a difficult time understating these things or controlling their bikes then I am not sure what to recommend except maybe lapping an open stretch of road in the national forest that has visibility for a distance and you have a way to herd your kids off the road when other vehicles come by.

Here is a NFS MVUM map of the area I am talking about. Most of these roads can be driven in a two wheel drive car. Many of them are rather smooth gravel. Some are a bit rocky in parts. I would recommend riding the roads yourself prior to bringing the kids out to be sure its what you are looking for.

http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5339603.pdf

I have a family membership for 250$ a year. 1.5 hours from Parker. Or 10$ a day per rider. Mini track and flattrack for new riders. Big mx track for all.