Check the keel and the rigging . . .
The Cat 22 is a very good boat in that it does everything fairly well. Your greatest issue will be the mechanical condition. The swing keel should be inspected at the hinge(pivot) point for any looseness, movement, etc. (any movement is a bad thing) Check the cable for fraying and other signs of wear.Check the rudder for splitting. If it is split, then it is a throw-away.Check the rigging for completeness and good condition.If it has a trailer with an extendable tongue, check to see if the tongue extends (they seize up really easily, King Kong would have a tough time getting it apart)The nice thing about the Cat 22 is that you can still buy all the parts. ( www.catalinadirect.com )