I'm thinking along the same lines as the OP, a lot of single handing, trips up and down the east coast, with possibilities of the entire loop someday.
Right now my balance of boat, which is the largest I think I can singlehand, the smallest I want to liveaboard, and within my budget (OK I'm putting my flame suit on for all the heat I'm going to get for this) is one of the 1990-1999 SeaRay 500 Sundancers.
Going for the larger format single level boat, I think will be easier to manage over a smaller multi level trawler style. Longer and wider yes, but less windage and no stairs. Bowthruster mandatory, along with remotes for the windlass. Will have to see about stern thruster. Biggest issue now is downsizing the ancient, unreliable, fuel guzzeling Detroit 6V92's that are in most of them, and repowering with possibly either Cummins 6BTA's or Cat 3208's or similar.
Yes, I know, the hull is inefficient above about 10 knots, but thats the whole point, It's for cruising the speed regulated intracoastal. It's got a 15' beam and 4'draft, so put the little engines in, kick back, relax and enjoy retirement, LOL.