The Tower Climb is by far the most difficult part of any ride at New Melones Reservoir. The climb is not steep for any extended period of time, but there are some short steep segments which may cause you to loose traction while climbing them. There are about 10 switchbacks and they are a challenge to clean both uphill and down. An alternative climb is a real lungbuster up a fireroad that parallels the road and goes to the top of the tower climb.
Like most of the trails here the descent down the Tower Climb mostly consists of fast hardpacked singletrack which can be very fun. The switchbacks and a few of the curves are a bit scary because of the cliff face but most beginning singletrackers will be able to clean everthing here except for the switchbacks.
For those who live in the San Joaquin and Stanislaus County areas the Glory Hole Recreation Area offers some of the best singletrack for beginning and intermediate rides. If you are a more advanced rider you can focus on the Tower Climb and on the Fireroad climb to build endurance and switchback skills. This area is also an excellent winter trail because it dries out quickly and the trails are quite rideable soon after a rain. Overall if you live in the area or are going to be visiting near here it's an execellent trail system.