Emily- just saw your comment. Mt. Lemmon is not so much hard, as just a long, constant climb. The grade is mainly 5% and so it's just a steady uphill slog. I average 6-7 mph when I'm moving but I stop every few miles and take a little rest.

Last trip I stopped around mile 7 (mainly due to time constraints). This trip, about mile 9. Next trip I'll go to either 11.5 (Middle Bear Canyon) or Windy Point (mile 14).