I have a 1992 Mac 26S. I bought it early last year. Here is a list of things I've had to work on as a result of buying an older boat.
Trailer Work: new guide posts, lights, tongue jack, bunk boards, rubber accessories (required for my boat)
Sail Work: new genoa (required for my boat)
Running RIgging: all new (but this was my preference, it was not required)
Standing RIgging: likely new next season
Rudder Work: new glass covering a hole (required for my boat)
Motor: new motor (died on second sail) (required for my boat)
Cushions: new covers (wife's preference...not necessarily needed)
Tiller: new tiller (two, i busted the first one with machinery used to drill holes...DOH) (required for my boat)
Fuel: Decommissioned old tank, filter and lines. Installed simple 3 gallon portable tank with new lines running to new motor (definitely required)
Electric: All new save the breaker panel (required for my boat)
Mast: the base is pretty knarled up, but i haven't replaced. if my mast fails, i'll take it as a cosmic sign that it's time to buy another boat
Interior Lighting: all new (required for my boat)
BBQ Pit: b-day present and i love it
I basically overhauled her as she was in pretty poor condition. it's much cleaner and it smells better which means my wife and kiddos enjoy it more. I have some more glass work to do on the body of the boat. I have hull blisters to deal with one day. No major leaks from the bottom, but I get water from the top when it rains.
This boat is wonderful to me and is basically my sailing university for the next boat. I'm learning alot more about boat maintenance and preference than I ever did on my Hobie Cats. I had no experience with fuel, electricity, or fiber glass. i'm thinking of refurbing the hull in the next season or two just to learn how to do it and to get rid of the blisters. I am not worried about racing her as i know she is slow. But that's okay with me. I had my fill of racing hobies.
I notated what was required just to get up and running. I knew what i was getting into when i bought it. I wanted something that needed some work so that i could get the education i've needed to be a better sailor!
I don't know if that helps, but i hope it does. I just thought i'd chime in since you're looking at the boat i have.
Bryan