A great trail system built and maintained by RASTA (www.rastatrails.org).
Need to Know
There are two trailheads. The old one that still exists near Washburn Lake and new trailhead at the lovely Perch Lake Shelter. Use either but the trail flows best and has most options from the nice shelter.
Cross country ski trails and singletrack cross in this area so a beginner can ride XC trails or exit singletrack.
It's best to ride this loop clockwise. That's head north and east first from Perch Lake Shelter. That way you're going downhill when you hit the excellent berms and bridges exemplified by Joz Way, and same for the return to shelter near Perch Lake.
Joz'Way on the east side has some great berms, and other parts of the east side feature bridges and spots to pump your bike. Joz Way is named after trail builder Al the owner of Bikes-N-Boards in Rhinelander.
The RASTA crew keeps at the good work. You'll encounter some old school singletrack on fall line but see new work is designed well. Each year the old school trail in need of work gets improved.
Kathy's loop within the main loop is new and the suggested way to make the loop.
The inner loop near Perch Lake shelter can be a good way to start. If that's too rocky or steep you'll know what is ahead.
You can mix the cross country ski trail and Kathy's loop to the Perch Lake finish for a beginner or fast route.