Turn off of Raccoon Mountain Trail at the Yellow Diamond markers. This trail is marked for CCW as the main direction. Either way you decide to take this loop, you'll have a tough climb followed by a wide open downhill.
After a nice spillway you'll hit a set of old foundations; take a deep breath and sip of water because at the next marked intersection, the climbing begins. Right is the Upper Bower Field Trail and left is Lower (less elevation and much shorter). Take the right and push yourself up to the metal gate which you'll currently have to go around and then continue to the top.
There is a marked singletrack connector at the top before heading back down. Unfortunately, there is another gate to make your way around before the descent. The descent is marked with directional arrows where needed. After the foundations, you'll find the intersection with Lower Bower where you'll want to take a right along the stone walls. You'll end up on the common connector and return to Raccoon Mountain Trail..
If you choose the Lower Bower Connector
during the climb, you'll have a much shorter climb. Follow this CCW just as the Upper's description and enjoy. Lower Bower Connector
actually connects both sets of really cool building foundations.