I have family in the UK, but they're not really into sailing... either side of the pond, principles remain the same. At the marina & sailing club where I used to work, there were several options: pay moorage or slip fees (fairly expensive), keep a slightly smaller boat on a trailer and pay lot storage fees (much cheaper), or keep an even smaller boat on a rack (also much cheaper). After reading your post, I'd say buy a 22' to 27' sloop on a trailer and use a ramp or hoist to put her in the water. Some marinas Stateside are laid out in such a way that you can leave your mast stepped and standing rigging in place, no clearance issues in launching... a big plus, as less time is wasted on tedious rigging every time you want to sail. Also, you can put a 30' sloop on a trailer, no worries, the question is how much will they charge you to keep the boat in the parking lot?
Might wanna ask various marinas, you can save time by doing it on the web... that'll narrow down your choices, at which point you can go suss out each marina to see the layout and get a feel for the place, talk to the manager, maybe talk to some folks on the docks to see what they think of the place. Bar or snack bar too, those are good places to ask questions if locals are in the mood to talk. That's my advice... unless you plan on cruising later, you don't really need a 30' boat for a family of four, though a larger boat is nice. Depending on how young your kids are, you could comfortably sail a 22' to 27' boat and keep her on a trailer, preferably with the mast stepped and standing rigging in place... best of both worlds that way, and heller cheap compared to moorage or slip fees. Don't forget, you'll probably have to show proof of insurance for any boat in the water, and possibly some stored on land.
You can also judge how well a marina is managed by checking the grounds & docks, checking the cleanliness of heads & showers on shore, seeing whether the food is any good in the restaurant or snack bar, etc. If you're gonna do this, ya might as well do it right and pick the best possible overall choice of marinas to suit your specific needs. I've known quite a few liveaboards too, and little things can make a big difference when it comes to happiness, LOL. Working at a club or marina also gives one the perspective of staff members: good staff usually want things to run smoothly, bad or lazy staff don't give a damn, it's just a job to them. I was lucky, we had dedicated staff members at our club & marina, and we generally got along well together. If you do this whole marina thing, try to cultivate civil relationships with useful staff members, as they will be more willing to help you out in the long run.
GOOD LUCK TO YA, AND DON'T FORGET TO KEEP MARINE SAFETY YOUR TOP PRIORITY, AYE? CHEERS!!!
