Check these boats out like you are the insurance adjuster quoting the policy for a classic antique, not the proud new purchaser. The boat could be beautifully appointed and shiny, and be a complete lemon. As I am slowly learning, there are lots of big heavy expensive parts on the boat hidden behind all the shiny teak. Some, like the steering pedestal base, or the engine's timing gear cover, aren't even available for purchase anywhere except used at random wrecker yards around the country. Without a working engine you have faith in you'll get that sinking feeling the first time you turn the key and hear nothing. Just about every other part of the boat can be fixed or replaced by yourself or competent general craftsmen as needed. Sails, rigging, heads, ovens, tanks, electronics, wood, etc. are all "nice to have". Keel, spars, engine, transmission, solid deck core are what you'll want to start with in good shape.
Of course if the boat is dirty and in general disrepair, odds are the important bits are in bad shape as well. Unless you are a real tinkerer, you'll want to be out sailing right away while she slowly ropes you in, so make sure a survey shows the boat to be generally safe to take out, and make sure to keep some purchase price in reserve pending a real sea trial where the engine and rig are used for a few hours at least. The rest of it is just "boat work".
The boat itself is built very well, performs very well, has stood the test of time and will always reward your investment of time and money (and then ask for more!)