In addition to Camelback, there is the Circumference Trail at Piestewa Peak. If you combine it with the summit trail, it is a little over 5 miles and is quite pleasant and peaceful until you meet the summit trail.
There is also Pinnacle Peak, 4 miles RT(to the gate).
The McDowell Sonoran Preserve has many miles of trails for every taste and fitness level.
This website gives all the info you could ever need.
http://hikearizona.com/