I did this one a while ago, but numerous people have asked me about it: The Gore Lake – Deluge Lake Loop. This loop hike can be just about as strenuous as you want. It’s not too bad provided you’re in reasonable hiking shape.
The route: Start at the Gore Creek/Deluge trailhead way down near I-70. Follow the Gore Creek trail to Gore Lake (taking a left turn to Gore Lake instead of continuing onward to Red Pass). Stop for the night at Gore Lake. Then, hike on to Snow Pass, the high point of the loop. There’s a rocky trail down to Deluge Lake where more good camp sites can be found. Finally hike out the steep Deluge Lake trail.
Bonuses: There’s lots of peakbagging opportunities along the way. All are easy scrambles. We did: Hail Peak, Snow Peak, and Mount Valhalla (which required the most scrambling). Try Grand Traverse Peak if you have the energy after Valhalla. We also made a hike up to the Zodiac Spires through a huge high alpine meadow.