seek advice on offshore cruiser
From your post above it looks like you are looking at older (70''s vintage) boats for cruising. Your budget is probably adequate for this. Keep in mind a couple things to begin with: 1) older boats needs more $ to get them ready for sea, electrical systems may need upgrading etc, 2) older boats have more austere accomodations that similar sized new boats and 3) Equipping the boat for cruising/livaboard/ offshore will take a significant amount of cash after the sale.
The boats you list above are all very different. The Cal 39 is a sturdy and FAST boat, it carries a lot more canvas than the others mentioned. I think it would be harder to single hand than the others mentioned. The Downeast, Alberg and Allied Princess are all well thought of, but very very slow and cramped by today''s standards. The Alberg especially - though it has beautiful lines and many couples have cruised on them... but they are very cramped.
And you mention after cabin, for $65k on a 36-37ft boat. I do not know of any boat that fits that criteria (except for perhaps a Catalina 36 or Hunter 37.. but not sure if these are appropriate if you are really going offshore). I do agree that an aft cabin (even a quarter cabin is very very nice to have. Boats of any size are not a lot of space to live on. In my opinion, dividing up the cabin with more private cabin''s helps to make a boat more comfortable and private for everyone aboard.
There are many people here much more qualified than I who, hopefully, will give you some good recommendations. I will suggest you look at a couple different boats, one 70''s vintage, one 80''s vintage and then make a list of your absolutely required criteria and which of those criteria you are willing to compromise on (like private aft cabin, price etc).
For a livable boat that can be single handed, my choice was 38ft. One boat you might consider would be an Allied Mistress 39. They are ketch rigged, center cockpit with a large private aft cabin. They are not fast but not slow and can be had at a very attractive price. Allied''s have a reputation for being well built offshore boats.
Hope this helps