I bought a "75" Catalina 27 with a poor interior arrangement - the "dinette model." It was one of those bare boats that the previous 3 or 4 owners apparently couldn't or wouldn't spend a dime on it.
Getting a bare boat and fixing it up isn't all bad. I enclosed the pathetic transom rectangle to hold the outboard and instead had a power bracket installed to raise and lower the motor. The motor is new; the electrical will be new - very little existed as you will discover on an old boat. Through the hull levers were replaced, as recommended in Don Casey's book. New electronics are in the process of being added - already bought but waiting for batteries, inverter, etc to be added, along with the already installed new electrical panels.
Working with a bare boat is like working with a clean slate; the basic boat is older, but everything added, improved upon, re-bedded, etc gives you a newer modern boat. I don't have to worry about a new engine, crappy old electronics, poor rigging, etc. I know what I have because either I installed it or had it done professionally.
The nice thing about getting an older "over spec'd" boat is that popular (such as my Catalina) is that there are a number of good forums to help you out. Often if you want to do a repair, like re-install the old windows, I can find a few who have done it, tell you how, and have pictures to back up the text.
Here's one link as an example of text and pics on how to repair items for my Catalina 27:
Or you can go over the top with modifications and improvements as this guy has done:
So if you get an old bare boat, you'll end up with a strange concoction of brand new and older, but you'll know about boating repair and maintenance, and know exactly what you own.