If you have a car and don't mind a bit of a drive, these are some of the things I saw in my multiple day trips while staying in Mammoth this year:
Twenty Lakes Basin (Saddlebag Lake, one of John's suggetions) is something I'd like to do.
There's a spot to view the Minarets just to the north of the entrance station to Devil's Postpile. It's a nice spot to watch the sunset or sunrise.
The next time I am in Mammoth, I hope to do some hiking closer to Mammoth. Have any of you hiked Banner Peak or Mt. Ritter?
