Total elevation change: Over 200 ft.
Average Grade: 2%. But that's average. Here are some of the bigger hills:
 

Tunnel Hill:	The hill leading down to the tunnel drops over 90 ft in less than half a mile, a 4% grade. The part just before the tunnel is very steep.
Big Hollow Wooded Return Path (summer):	The return path out of Big Hollow near the end of the run ascends a short, but very steep footpath and connects to the bike path near the top of the hill. The ascent is 130 ft over about half a mile. The steepest part of the climb up the footpath is a 9.6% grade!
4 Hills (winter):	A 94 ft rise over 0.32 miles: 5% upward grade.

 

After making the obligatory hooting sounds through the tunnel, bear left on the footpath that starts just past the exit of the tunnel. This path goes through the woods for just under a quarter mile. It T's at the gravel part of Big Hollow Rd. Make a left here. Continue on Big Hollow Rd to Fox Hollow Rd. Go left at Fox Hollow Rd, crossing the road as it goes under the bridge for Rte 322. Make a right immediately onto the macadam-paved part of Big Hollow Rd. Just over half a mile down the road, Big Hollow Rd bears to the left to go up "4 Hills". You can return this way (see below), but during the months of April-November, it is more pleasant to come back via the footpath through Big Hollow. To do this, veer off of Big Hollow Rd at the small blue cinder block building at the bottom of the hill. A footpath heading to the left through the hollow can be seen. Follow this path as it winds through the hollow. About a half mile later you will see a path that heads up the steep hill to your left. It is a couple of hundred yards before the Sunset Park bike path. The climb is very steep. The path then winds through the woods and comes out of the woods on the bike path just below Sunset Park. Make a left on the bike path till it ends. Continue up McKee St. Make a right on Adams St, a left on North Burrowes, cross Park Ave and enter the campus at the entrance to the Nittany Lion Inn. Continue up the sidewalk to finish at Rec Hall.

During the winter and early spring, the snowed-under or muddy conditions of the Big Hollow footpath can be avoided by continuing up Big Hollow Rd, up the "4 Hills" to Services Rd. next to the Penn State Salvage Building. Go right on Services Rd., follow it as it bears left and becomes Bigler Rd. Carefully cross Park Avenue and continue on Bigler Rd. to Curtin Rd. Take a right on Curtin Rd. and head back to Rec Hall. This substitution adds about 0.1 miles to the route and avoids most of the treacherous parts of the loop.
 

The winter route substitutes the "4 Hills" climb up Big Hollow Rd for the grassy footpath through and out of Big Hollow. It avoids most of the "tough sledding". However, the winter route has a stretch of about 0.2 mile that may still be treacherous in the winter months, especially if there is deep snow or ice. The part in question is the stretch through the woods just after the tunnel and before the footpath connects to the gravel part of Big Hollow Rd.