Favorite 2-3 day loop East side Sierras

A loop of 20-45 miles is difficult from the east side. Most of the trailheads require 7-8 miles to go over a pass (and thus you've used up 15 miles on an out and back before your loop starts) leaving you with only 5-30 miles of "loop". Arranging a shuttle opens up a lot of options–like Onion Valley to Whitney Portal, South Lake to North Lake via Muir Pass (You'd have to go over Lamark Col which is an easy XC pass and it's still around 40 miles), Duck Lake to McGee Creek.

A modified version of Kevin's first route would be to come out over Shepherd Pass, with either a shuttle pickup to get you back to Onion Valley or walk about 3-4 miles of gravel road to Onion Valley Rd and hitch a ride back up to Onion Valley. The Shepherd Pass trail goes through some spectacular country(as does the route to Whitney Portal), and it is a lot more enjoyable going down than up for most folks. It is also somewhere around 12-13 miles shorter, which might might make it a good "first East Side" hike. Also, thinking ahead a bit, if you like the Shepherd Pass trail keep in mind that it offers the most direct entry into the Kern Basin(IMO about the creme de la creme of Sierra backcountry). If you are fairly fit and travelling light there are several 3-4 day "on the move" trips it offers, e.g Wright Lakes Basin and Wallace Lake Basin. These, in turn, may entice you further into Kern country over toward Milestone Basin and the Kern headwaters on longer trips(5 days minimum to allow a couple days to kick back and enjoy). Whatever you choose on the East side, it's hard to go wrong. Best of luck.