Be aware of compromises ...
Especially in a boat under 30'. You want a boat that is roomy enough to sail with frequent guests and you want a boat that handles overnights with the family ... in the first case you want a very roomy cockpit and in the second case you want a comfortable cabin. You won't get both. The parameters you mention seem to indicate that the largest boat you can afford is better. If you get a boat under 27' you will probably get 2-foot-itus almost immediately.
I'd day our boat has a fairly comfortable cabin (except for headroom if you are 6' as I am)for a 27' boat but the cockpit doesn't work for more than 3 adults, and even 3 is a crowd. However, our boat trades off headroom for performance, with a nice sleek profile that I think is more attractive. I also like that our boat is faster than most boats in her length, but it may not be important to other people. The beamyness of our boat provides nice wide side decks and teenagers love to sit on the deck, hanging on the lifelines with their feet over the side like the rail meat you see in the racing photos. The point is to look at all the features. Admittedly it is hard to know what the issues are until you gain experience.
Everybody has their own preferences, but I would steer you to a fixed-keel (fin or shoal draft) spade rudder style boat. You will trade off performance for comfort (particularly headroom). I would point you toward an inboard diesel ... in my case, I wanted to learn about diesels so that I was prepared when moving up, and I just don't like an outboard spoiling the lines of a sailboat.
Have no hesitation about a 70's or 80's boat that has been maintained well, but look carefully. DON'T get involved in a project boat that doesn't fit your needs and desires immediately ... your wife and kids may not have the patience. If it literally smells bad, move on (I learned the hard way) ... a boat with holding tank odor that permeates the cabin takes a lot of effort and time to eliminate. Cushion fabric and foam is very expensive to replace. DO get a boat with decent head.
That said, some projects are not essential and can be done over time and can be rewarding for your own enjoyment. This includes adding hardware for sailing convenience, or instruments and electronics. Or renewing the sail inventory. Or varnishing the brightwork and painting (say the mast and boom). Those types of things you can consider as upgrades that you can take time to do.
We store our boat at a yard with the mast up, with a custom cover and we don't have a trailer. There is a trade-off for not having a trailerable boat, but trailering a sailboat, as opposed to a ski boat, is a major hassle in my opinion. But I will acknowledge that there ARE perfectly valid differing opinions in that regard! Storage over the winter for us is expensive, for instance.