It sounds like you are looking for a boat that can carry some weight yet will be relatively user-friendly. I would suggest you think boardless or at the very least, centerboard boats rather than daggerboard ones. Boardless (affordable/not new) boats are Nacra 5.O and 5.7, Prindle 16 and 18, Hobie 16, and all the G-cats. I'd rule out all the 16's based simply on size. I have no personal knowledge of the G-cats. P-18 is an asymmetrical hull vs. Nacra 5.7's symmetrical one; the Prindle will point a little better but the Nacra will be a bit faster (absolute top speed) and a bit wetter.

Centerboard boats are Hobie 17, Prindle 18-2, Prindle 19, Tornado, and Hobie 21. Hobie 17 is a singlehander and will handle only about 200 lbs competently; both Prindles are good choices due to weight-carrying abilities, beam, and overall weight under 400 lbs; Tornados are quite affordable for the older non-competitive ones (non-Marstroms) but are overwidth for towing unless disassembled or using a tilt trailer, and the Hobie is heavy.

Finally, the Supercat 17 and 19, while daggerboard boats, would make good choices as well. The 19, particularly, was offered with or without daggerboards, but the hull shape was not changed; the dagger wells were just omitted. You could take a 19 and sail it either way; Bill Roberts, the original designer, told me a couple years ago when I was contemplating buying a 19 that if I wanted I could make plugs to fair the daggerwells and the boat would sail just fine without the boards.

good luck