All dirt/sand. Mostly level with some steep climbs and decents, depending on which path you take. The Perimeter Trail is for beginners, with other connecting trails for more advanced riders. Watch out for ATV's.
Very near central Waterloo, Iowa. Just off of HWY 218. Dedicated as an ATV park, but great for MTB riding.
http://www.singletracks.com/item.php?c=1&i=3935