CAMP 4 - last minute camp site

[rowzz2]

I plan on going July 31- Aug 2 and dont have reservations. From what I've read online CAMP 4 is a first come first served site and I have to get there early to get a site. Does anyone have any info on this?
-How early on a Friday morning do I have to arrive?
-Is it pretty likely there will be sites available or is more realistic that nobody will be leaving that day and I wont get anything?
-Are there any other first come first served sites around the Valley?
Thanks!

[AlmostThere]

Camp 4 is a walk in campground - you park and walk (less than 1/4 mile) and they put people six to a site, whether the other campers are part of your group or not. This is also where a lot of the climbers camp. I would get there in the morning on weekends in the summer. Later in the year it will not be so bad.

Bridalveil is entirely first come/first serve - it's on Glacier Point Road and is a car/RV campground. Half of the Tuolumne Meadows and Crane Flat campgrounds are held back for first come/first serve. Again, in summer, earlier in the day increases your odds of getting a site radically. You might luck out and get a cancellation as well.

If you do any backpacking the backpacker's campgrounds are available to you the night before you depart or the night after you come out of the wilderness for five dollars per night - but you must have a wilderness permit to stay there.