bakes, I was in the exact same position on Closing Weekend last year that you are in now. I also had a cast that went up to my knee.
The first thing I did was go to Park Operations (by the arcade area) and talked to them. I was given a little booklet (Rider Safety Guide) with sections for each of the coasters where I could get "boarding times". The way it works is that you go to a coaster, say Raptor, and say it has a 1 hour wait. You talk to the ride host at the entrance, and they will give you a time to come back to ride, approximately 1 hour later (the estimated wait). When you return, you can use the special access entrance to get to the front of the line. This way, you can't really take too much of an advantage of the system. However, I was able to take advantage by getting an MF boarding time, and until then waiting in shorter lines like Raptor or Magnum (I crutched, this may not be possible w/ a wheelchair).
As for coasters I couldn't go on, I wasn't restricted from riding anything.
I myself crutched around the park, however at the end of the day my arms were DEAD so I would recommend getting a wheelchair from Park Ops.
Oh and also you won't need a doctor's note, the people in Park Ops will assess it and almost definitely give you the Boarding Time booklet... I don't see why they wouldn't (even though I was somewhat able to manage crutching around and waiting in some lines).
The only regret I have of the day was the strength I lost in my arms ;) Other than that going to CP with a broken leg you will have as much fun as always!
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Steuks!!
*** This post was edited by Majin Heero on 6/5/2001. ***