In reply to timjones:
> Don't get sucked into having to stay in the valley. It will be cooler higher up so it's worth considering drive in campgrounds such as Porcupine Flat on the road up to Tuolomne Meadows.
This is a great idea for the time of year. I was in Yosemite late April/early May last year and only allowed 7 days camping in the valley. Dropping down to a campsite in El Portal at the end of the day, for the rest of the time, and seeing the temperature gauge rise by 10 degrees, was grim for cool weather loving me.