Sweetwater Preserve is a very popular trail system for mountain biking and hiking, and occasionally you might even see someone on horseback. There are quite a few trails but it’s fairly easy to ride all of them in a single visit. While the trails roll, there is no sustained steep uphill, although there are quite a few short rocky sections that can be quite difficult.
Unlike the Honeybee area, Sweetwater is well marked, with signs at every intersection, making it easy to figure out which way to go. In general the trails are too rocky to be enjoyable on a gravel bike. The one exception is the Desperado Trail, which is not desperate at all, and would be easy on a gravel bike.
Drive west from Silverbell on Camino del Cerro for about 2 miles to Tortolita Road, following signs for Sweetwater Trailhead. Turn left and drive for about a mile to a big dirt parking area and the trailhead.
A great way to ride the whole area is to ride around the outside (about 10 miles) then, if you want more, do the trails in the center (about 5 miles), all of which you can do in a morning. I suggest doing the following.
First, the outside: Saguaro Vista – Black Rock Loop – Sun Circle Loop – Lost Arrow – Homestead – Red Canyon – Red Tail Ridge – Night Hawk – Desperado Loop. This gives you a good feel for the area, with lots of rolling singletrack, and quite a few very rocky sections, many of which I walked, finishing with the lovely easy Desperado Loop.
If you are up for more, head into the interior and do Roller Coaster (partial) – Wildflower Ridge – The Spine (out and back) – Ocotillo Hill (out and back) – Wildflower Ridge – Desperado (to the parking area). Ocotillo Hill was one of my favorite sections.