I've enjoyed my Monk 42, but for health reasons, must now begin marketing her. And she would fit your requirements quite well.
"We plan to travel up and down the coast, do the loop and the Bahamas.
I want to be comfortable and a good floorplan. Living area vs seaworthiness is a balance I am striving for."
This brand is renowned for long-distance voyaging, with many such trips aboard the Monk 36, the little sister of our Monk with a LOA of over 45 feet.
"I have a sleep disorder and normally cannot share the bed with my wife, besides, she goes to bed early and I stay up late...so from what I see most floorplans have a fwd master with a center-line bed and a small twin bunk guest room. Can this be converted into a larger bed for me maybe?"
With 2 sizable cabins, fore and aft, there's ample sleeping accommodation for both of you, and without disturbing the sleeper. The aft cabin features a queen-sized pillow-top mattress on a peninsula-style bed. And the forward cabin features twin full-length berths. Each cabin has a solid teak privacy door, so no light transmission possible from late night activities.
"Can a vessel such as the Mainship 39 go to the Bahamas and stay for a season?"
No problem with our twin-engine Monk.
"Can it go further such as the BVI?"
"I see there are options such as twin Diesel or single...I am OK with a single for economic reasons..how much of a factor would this make in the decision?"
In my opinion, a boat of any size over mid 30's, particularly for long-distance travel, should have twin diesel power. Two engines will each work less than one engine alone. And the advantages of 2 engines goes further; think dead-slow steering and docking. And if you're out in the middle of big water, how would you feel about losing your only single engine? With twins, you have the ability to power your way to port without using a paddle.
"Does anybody ever add Solar Panels to supplement the Genset?"
I'd planned to install solar panels on the hard-top of the bridge. Lot's of real estate up there.
"Havent seen a trawler with a watermaker? I would like to install one....good idea?"
Rather than a water-maker, I use a portable Berkey water filter system. Check them out first; there's great!
I invite you to check out my boat which I just listed today. And remember that you definitely have the dollar exchange advantage with your American Greenbacks.