If you are looking for beginner to intermediate riding around the Front Range; I would suggest Buffalo Creek area. Just do a search on the forums here and you will find plenty of information. In my opinion most of the Front Range riding near the Denver Metro area would be difficult for beginner/intermediate riders. Besides the Buffalo Creek/Pine Valley Ranch area is some of the most buffed out single track I have ever ridden. The majority of the riding around the Boulder/Golden/Morrison area is great, but technically difficult and steep.