I sail a '77 Cal 29 and will second Sara's statement that they are laid out really exceptionally and spaciously. I am 6'3" and I fit in my boat
whereas I have friends who have 32'+ sailboats which I couldn't spend 10 minutes in without a sore neck.
I have found that the older cals are solid, simple and dry boats and for me, that has translated into savings as the quality of the boat has stood the test of time and doesn't require costly work to maintain it.
I have been on a friends cal 28 and found it to be similar to mine, both in it's simplicity and value. They are fantastic boats and you would do well to check some out.
Both my 29 and my friends 28 are over 30 years old, and both will be sailing in coastal BC this weekend with families on board... That is build quality to me...