Just an FYI I'm sure you've looked around BUT just in case something to think of.
They made somewhere in the neighborhood of 15000 of these boats. I believe there are more of them than any other boat out there that I know of.
The prices range from 1000 to about 7500 (yah I know there are fringe prices but that's the average range from bad to pretty damn good)
A 1000 boat is probably gonna cost you 5000 to get it up to good condition (again always the exception)
Don't get excited about one boat because it's available. Remember there are 15000 out there to choose from.
Some people (like myself) have spent an insane amount of money and when I do sell my boat I wont be keeping any of the upgrades and it would all go with the boat and would be an awesome deal for any buyer.
Unless your looking for a project, and a lot of people like a project and that's cool to don't buy a project boat just because it's cheep. Again your gonna buy yourself right into expensive again by the time your done.
Most expensive things?
Sails, there are cheep and expensive and really expensive. Wore out sails make a difference.
Auto pilot
Bimi
Battery's and solar panels
Depth/Chart plotter's (prices are all over on these)
safety gear, anchors and all the little crap like covers, pop top netting, hatch netting, screen door maybe.
Interior stuff like bedding, stoves, table, cushions, (I have memory foam bedding in both vbirth and lazeret so it's more comfortable)
Look at condition of all the lines, shackels, and connections that stuff adds up quick for quality.
Check big time for any squishy parts of the deck it shouldn't move AT ALL to fix a spongy deck is a big deal and major project.
Check the keel if it's swing keel it's gonna have some rust it's cast iron and 99% chance it's gonna have rust. Don't freak out over the rust but the amount does matter. If it has chunks missing that's an issue they are hard to come by and not horrable but a pain in the arse to change out.
Bottom paint well that's just something that needs done now and then.
Look inside if you see water stains on the walls depending where then you might want to walk away in my opinion not that it isn't fixable but to me it means the previous owner wasn't keeping up with maint and that's bigger than anything else.
Anyway theres more stuff but this is the quick list I could think of off the top of my head.
Just remember again there are tons and tons of catalina 22's for sale out there in any given period of time and it's easy to get excited about one you find just remember if the previous owner wasn't sailing the boat for a period of time it's probably in need of a lot. move one to a better one.