The GPS data is used for fetching and plotting the USGS elevation data.
Due to the dicretization of the GPS track data, the track length
is usually 4% or more shorter than the actual trail length.
For example the wheeled length of the Piney River trail is 8.46 miles,
while the GPS track length is 8.1 miles (which includes adjusting
for elevation "distance").
The cumulative +climb/-descent is calculated
from the USGS elevation data and is smoothed by a 10' filter, but even
still the estimates are probably quite high.
(Elevation data collected by the GPS is typically less accurate than
fetching the USGS elevation data.)
Based on the elevation data, the steepest half-mile sections are
Lawson Mtn (mile 2.2 to 2.7 25%, 6.5 to 6.9 23%, 3.6 to 4.1 22%),
Arch Mtn (3.6 to 4.1 22%), and Cross
Mtn (12.2 to 12.7 22%).