OK
1) For free camping, DON'T just pitch a tent or assume you can sleep in your truck in the Smoke Bluffs or Apron parking lot even if you see other ppl doing it. You aren't supposed to and if it becomes a problem the resulting crackdown will be bad for everybody. tHere are all sorts of free camping sites available. You can camp for free anywhere on Crown land. The problem is finding it. Highway pullouts do not count. The closest sites to downtown Squamish are about 10km up the Mamquam road (the one that starts at the Apron), past the power project.
2) For pay camping, good non-chief options are at Cat Lake, Alice Lakes, or any one of various privately run campgrounds. Or, stay in one of the hostels.
3) Climbing Diedre on this weekend will be a traffic jam. It will take 3 hours to climb one pitch and passing will be impossible because of 10 climbers at each belay. You should climb Banana Peel or Calculus Crack instead because they will still be crowded but only half as crowded. If you want to climb Diedre, put your headlamp on and start at sundown.
3) You should check out Octopus' Garden, Funarama, Murrin Park, Seal Cove, Campground Wall, Easter Island and Chek for your climbing needs.