Stu's right.
I too had a Cataliana 22 (1979) for 6 years and then 'upgraded' to a Catalina 30 (1977).
Being an older boat, the price was right ($9,500), but I had to replace the rudder, I rewired everything (thanks to Stu :dance

and replumbed everything (thanks to West Marine, Jamestown and Defender :dance
The boat has it creaks and groans...but the main thing that would keep me from buying her again are the issues that Stu mentioned.
I just know the compression block under the mast post in the bilge is probably rotten. The keel bolts are a mess and it is impossible to get a socket on them to try and tighten. I have the "Catalina Smile

" and I have ground it down and recaulked and fiberglassed the enter keel to stub section. I dread going through the efforts of getting into the bilge and cutting down to the actual wooden stub and redoing the entire affair including the compression block.
Other than that....I LOVE THE DAMN BOAT!!!!
She sits higher off the water than the 22 and I feel SO COOL when I'm cruising out onto the Lake. Of course the 'bigger' boats don't look at me...but so what! Did I say I LOVE THE DAMN BOAT?
I sail alone often on Lake Ontario and the winds pick up and the wave action is always choppy when it does. She rides nice and she is forgiving!
I would go with as new as you can for $15-$20k, leaving money for unforseen issues. I like going on Yachtworld and SBO to look at other Catalinas...keeping up with the Jones so to speak!
Good Luck!
Chris