I would try the southern snowies. It's been a while (several years) since I've ridden down there, but there used to be some nice play areas close to the trail that were easy to find. The terrain was also easier for noobs and less traffic. I believe we used a parking lot by Mountain Home (not sure about name). It was only a couple miles from the colo. state line.
Plan on riding up the road and go up T trail as far as you can. Turn around if anyone is cold or wet. If all your group wants to do is hit a trail do a loop through keystone.
When you get back to the truck head over to the lodge and grab an appetizer or early dinner after you load the sleds up.