Seems like a reasonable goal. The trade-offs (single .vs. twin, etc. etc.) are of course the fun part for you, so don't let the forum's opinions take that fun away from you.
That out of the way, here's some opinions.
A planing (or semi planing) powerboat is only reasonable when
fuel is
cheap. That may not happen again for a long time (when the world's population drops again to, say, 500M people).
A non-planing powerboat needs stabilization. The only stabilization that is safe,
cheap, reliable, and actually helps rather than hinders is a steadying sail.
Twin .vs.
single is almost a religious issue. Strong pros and cons for each. Personally, I prefer
single, having owned both. You can't run ANY
boat without some practice. With some practice, a single screw is amazingly maneuverable. Note the very many
commercial vessels that are single screw, its certainly the vast majority worldwide. I think spring lines are way easier and less annoyingly (painfully) noisy than a bow thruster.
Boating is far more similar to camping than to living in a house. So get a boat for
boating. If its got TV,
heating,
air conditioning, built-in vacuum, escalators, helicopter hangers, etc., you don't want to be the person running it unless the owner (not you) pays you well and keeps the expense account well filled with lots and lots of BOAT units (BOAT=break out another thousand). Dinghies are much more useful than Sat-comm or washer/dryers. Have fun, you already have plenty of
work if you've got the $$ to own a boat.
Any
wood structure (cabin sides, decks, transom, stringers,
engine beds, bulkheads, etc.) WILL
rot. Avoid. Its your choice, choose another.
Exterior
varnish is beautiful. For a very short time (weeks). And then its not. And then its a lot of work. Avoid.
Visibility from the
wheel is absolutely vital, and rarely well addressed. When its not very sunny and clear outside (and sometimes even then)
interior reflections will interfere with visibility from an enclosed wheelhouse. As will steam from
cooking nearly anything in the
galley. At night, most wheelhouses are quite difficult to see outside (ships!! unlighted row boats, bouys, shoals,
wind on the
water, landmarks, ...). Eisenglass is annoying (maybe "awful" or "painful" or "downright dangerous") to look through underway.
Unpowered all
weather ventilation. You will know immediately when you board a boat without it: it stinks, smells musty, moldy, or much worse.
Heads should be vacuflush or similar:
electric so guests are less likely to break or clog it; very low water usage so the
holding tank does not fill up in a day; and only use fresh water to flush to greatly reduce odors.
Showers are overrated. On some boats, I've had separate stand up stall showers that were large enough for two. On some, a "wet
head." On some, buckets on
deck. Each approach has clear advantages over the others: a stall
shower means the water stays in the
shower, but if not ventilated WELL these things get disgusting; a wet
head allows you to do double duty,
washing yourself and
washing the head compartment at the same time while also enabling the head space to be larger and therefore far easier to air out and avoid
mold (the entire head then MUST have smooth hard surfaces only with large corner radiuses); a bucket on
deck is all you will want south of, say, Ensenada, and is pretty darn nice in decent
weather far to the north. And don't you usually go boating in nice weather?