Anderson is a nice trail with 10 miles of singletrack, several long climbs and fast downhills, some BIG drops and, unfortunately, a number of sandy sections. The sand gets pretty bad during the summer, it's best to ride this trail in the Fall and Spring (and even Winter). If you want to get in shape AND at the same time work on your skills Anderson is one of the best trails to ride.
Most important thing about Anderson; this trail is on Private Property. Mountain bikers are welcome has long as we behave (I assume). So, Behave!
Drive East on I-240, take the Anderson Rd exit and head South to 149th. Or drive South on Sooner road and head East on 149th to Anderson.
http://www.singletracks.com/item.php?c=1&i=1395