The Pilgrim trails (across the road around Dragon loop) are great for beginners and challenging enough to encourage quick skill development. They're fun and fast trails for an easy ride for more advanced riders. Dragon Loop is very challenging - lots of funky little "stunts" here.
Time Trial is a favorite of beginners and advanced riders alike. It is a technical trail perfect for developing skills. Outer Limits (aka Outer Loop -easier) and Twilight Zone (aka Inner Loop - more advanced) are the longest loops that offer lots of downhill. There are some jumps on Outer Loop (go clockwise to hit these right). Of course, of course, what goes down, must climb back up. I've been dooped into climbing these repeatedly because the downhill is so much fun. Go clockwise on both loops to maximize downhill fun and shorten the ride up the hill.
Hairy Toad and Barking Frog are the rocky, curvy, rooty trails. These are very technical. The bridges on these trails are narrow planks - beginners should be prepared to walk if they brave these trails. They are great fun is you're looking for a technical ride.
The trails are very well maintained and constantly evolving. These trails offer a lot of variety for all skill levels and is a great place to develop you bike handling skills. There are even some freeriding opportunities sprinkled in.