Perhaps the best season to camp and day hike in the Sierra (either from
the west or east sides) is from Labor Day through the end of October.
Crowds are mostly non-existent, campgrounds relatively available,
mosquitoes not an issue (the first hard frost kills them) and it's
cooler.  It's the shoulder season - the summer people are gone and the
winter people haven't encroached.  Nights can be nippy but daytime
hiking is usually perfect 50 - 70 degrees, depending on elevation.

Jeff
Martin, SD