Probably would advise against anything resembling a Prospector for your stated use. I love mine, but it's not what I reach for when heading to the lake. Too vulnerable to the wind having its way with it. Yeah, you can do things to mitigate that, but unless this is a "one and only for all uses", there are much better choices for primarily lake use.
For “
mostly lakes, solo day trips and a few overnighters” I’d probably stay away from most modern Prospectors.
Maybe Clipper’s 14 foot Prospector solo, but that is still a lot of freeboard lightly loaded in the wind, and you won’t find one on the east coast.
http://www.clippercanoes.com/14-foot-prospector/
At your size, I think I would be looking for something 15' or longer and about 28-32" wide for a solo.
Yeah, at 5’ 11” and 230 lbs a lake sheerline depth canoe at 15 feet would seem a good choice, maybe a little less max wide than 32 inches.
Length depends on how you pack for an overnighter. If you are a gear heavy glamper you may not want much less than 15 feet for ample below-gunwales gear storage. If you are a gram weenie one-pack tripper the extra length is unnecessary.
Beyond length and width I believe the bottom shape cross section has more to do with my wobbly, seated paddler comfort considerations than anything else. When seated in a round/elliptically bottomed canoe designed for kneeling I feel like an inebriated pig riding a unicycle, and I really don’t wanna be on my knees all the time.
My personal acid test for paddling seated: Can I turn my head and torso to look 180 degrees behind me, or grab a small dry bag or Pelican box from behind the seat and swing it forward between my knees?
If I can’t do that, at least in unchallenging conditions without an instant brace, I keep looking.
BTW, “I’m retired”. Me too, and the lighter the canoe the more it gets used these days. At a certain age weight becomes a now (and even more so in the future) consideration, especially if dropping big $’s on a canoe you may be paddling for decades to come.
I still lust after a Placid RapidFire as a lake daytrip canoe. Hell, it might be enough to turn me into a gram weenie for weekend trips.