I don't think a single
engine is a show stopper, and in fact a single diesel
can be very economical. One of our dock
neighbors has a Carolina Classic, approx 25' or maybe 28' or so, with a diesel
, jackshaft, and outdrive... and he runs it from the Chesapeake down to Man O' War Key most years...
Sleeping 3 plus an occasional 2-3 more gets more to size issues, I think. Your family
sounds like 2 "staterooms" of some sort... and then you've got to consider where to stuff any visitors for overnighters. We are 42' with two staterooms and a fold-out bed
in the saloon
... but I seriously begrudge using the saloon
space for visitors. Partly depends on how much personal space you (and your family members/visitors) prefer, of course. Occoasional privacy -- and therefore some room to have some -- seems to be a good thing, when folks spend boatloads of time in each other's face.
I personally prefer diesels over gas, not just for mains but especially because of the genset, too.
V-drives seem to me to mostly be a big-time maintenance
problem; not because of their design, but because builders stuff 'em in so tight, access seems to always be problematic.
In fact, access to systems to service/repair stuff is another driver I use to chose boats. A two stateroom 34' cruiser will like have crappy access to fix anything, whereas a two stateroom 42' only has "difficult" access to a many things
I would not describe a Dancer 310 (a dock
neighbor has one) as suitable for any kind of long-term occupancy... especially because I prefer a more open saloon, with windows all around... and a flybridge... but that's just me, and obviously YMMV.