I just went down this same road. I ended up with an Aquarius 23', really too small for what I wanted, but a good first beginning.
Here is a project boat I was looking at. Clipper Marine, 32', 1977, Panama City Beach, Florida, sailboat for sale from Sailing Texas
It is setup for trialering, with roller bunks. A civil engineer boat ramp, (there are a few) have long deep ramps, the average weekend fishing boat launch generally has only 10-12' of cement before you are in the mud in about 3' of water. A full keel boat is NOT going to be launched there.
If you are only going to bring the boat in and out once a year, it may be worth it to go ahead and launch at a marina/shipyard. $200.00-$400.00 a year that includes pressure wash and mast stepping, plus the option of a bottom job for +-$1000.00 more, and your boat is set until next year.
I looked at the bigger trailerable boats, but found the word trailerable is a broad word. If it takes 8 hours for 4 men to put up the rigging, it is not something you can do on a weekend. Also if there are only two ramps in the state you can launch from, thats not really an option either.
Keep the options coming, I am interested also. There has to be aa affordable boat that someone else has done this with. Seaworthy enough to make an island crossing, (100 miles from island to island), in good weather, but easy up mast, (there has to be a locking mast step with a hinge).
I saw a Balboa 26 with a swing keel that had a locking mechanism. A wing keel is also launchable on a ramp 36' draft, but same stability as a fin keel, (slightly less righting moment). Some shoal keels are also ramp launchable. The trick is either redoing the mast step or finding one with a hinge.