Attributes of a Coastal Cruiser
I get the impression that you have not done a lot of sailing, forgive me if I am wrong.
What you should look for:
Books, in the library, there are tons of them on buying a boat. Personally I like Ted Brewers articles on the subject, he takes a complex topic and makes it easier to understand.
Some one with a boat who will take you sailing. If you can do this you really ought to a bit of experience will help a lot since much of boat ownership is finding the boat that feels right for you. At the very least take a few two hour sailing trips on different sailing school or charter boats. Tell the captain what your thinking of doing and you will get a sail and advice.
A good surveyor. I surveyed 2 boats before buying and in your price range survey is very important because the boat will not be new and you don''t want to buy a hidden problem. Also a good surveyor will talk boats with you while doing the survey. The guy who surveyed the first boat for me told me about the boat I own.
Just for comparison with the previous poster my boat is a Quoddy Pilot an 1850s design built in 1971. It has a head and I am writing this while avoiding the installation of a holding tank. It has 35 gallons of water which is fine because there is no onboard shower. It has a 12 gallon fuel tank which I can suppliment with plastic fuel cans if I feel the need. I like to bring along freinds and my cockpit seats 10. The boat sleeps 4 and is roomy below. It weighs 9 tons and draws a little over 5 feet but has a big gaff rig and it will also hit hull speed on a reach. Its a very comfortable boat. I expected it to be slow and I was suprised to find that it moves along pretty well, my best run was 70 miles in 10 hours of force 4-5 winds. Its also real pretty.
You can definitley get something that you will enjoy for $30k.
A few other things to look for:
Previous owner that cared enough to keep the boat in good shape.
For cruising I would avoid most older race boats because race boats often sacrifice too much comfort for too little speed. There are exceptions, I crew on a J30 that is a nice combination of speed, comfortable ride and comfortable living space.
Consider a boat that can sail in shoal water. It opens up a lot of nice possibilities. I was looking for a Meadowlark ketch but the Quoddy Pilot was a good deal so here I am. Sharpies are also worth looking into if your interested in this.
Learn about diesel engines. Its the one thing I wish I had known more about when I bought my boat. I know a lot more now.
Remember that new boats get old real fast but a well maintained old boat can be much more well maintained than old.
Tell us more about what your looking for and people may give you good suggestions about production boats that are worth a look. Personally I am a character boat guy so my suggestions and experience are more in that area.