1) Sharkskinz, hotbodies, cheetah race skinz, or check classifieds on the CCS forum, and WERA board.
2) Routine for unregistering it is just let your registration lapse, then don't renew. You can register it when you sell it as long as you don't ever turn an accident over to your insurance the title is still clean.
3) Nesba, STT, One of Ody's rented track days.
4) Depends on the organization you run with, but in general it's a good idea to drill and safety wire the oil drain plug, filler cap, radiator cap, oil filter (put a hose clamp around that one), caliper bolts, and cinch bolts for the front forks. Just drill them with a small drill bit through the center and get steel wire run it through the bolt twist it, then connect it to something that is stationary on the bike close to the bolt you are trying to safety wire.
5) There isn't a track specific schedule you have to just check the NESBA, and STT schedules to see which dates they have events at blackhawk.
Other than that have fun!