Split decision

How much is the budget for this purchase?

On the low end of your size range and budget- A mid-90's Hatteras 52 Cockpit Motor Yacht would be a decent choice. They have 2 nice staterooms + a bunk cabin, 3 heads all with stall showers, and a huge aft deck. Add to that a nice cockpit with a transom door and decent economy at displacement RPM's. You also have a fast cruise if you want it. Interiors are mostly modern, airy light wood finishes. You should have a good selection in the $300 to $350K price range.

Make sure what ever you get is stabilized.

And when you say "room for guests" how many guests are you talking about, 2, 4, 6?

Trawler economy does not have to equal trawler looks. Personally I don't mind the classic trawler look, but I get your point.
I have been looking for a boat in the 50' to 60' for a while, just add a fishing cockpit and we have similar needs BUT not budget. At your budget, there is an enormous choice.
Some examples:
Offshore 58/62, GREAT boat, I had a 58, 3 cabin 1996. PERFECT for cruising in most conditions, seaworthy, very roomy, large uncluttered cockpit, beautiful pilothouse, stabilised, ecomical at hull speed. I cruised the East coast Queensland and it was superb.
Or the 55 Offshore. This is older but also great boats.
To me these boats are perfect if you cannot go to Grand Banks quality/price, and Fleming low profile timeless design. BTW, good quality too... need I go on before I sound like a sales brochure? Yes they can be bought at good prices now.
Other boats to look at: Tollycraft 57, GREAT BOAT!!! but of the 11 or so built, be aware some were chartered.
Fleming 55 if you can find a good one at your budget.

Then the boats I am VERY keen on: HATTERAS 53 or 58 Yachtfish, and larger cockpit models. On these I will stand back and let the real experts jump in....Pascal, go for it...

I have travelled all over Belize, and unless you are staying in Belize City, draft is a major concern. The yacht I ran there drew 4' and we BARELY got in and out of San Pedro, Some parts of Glover's Reef (Southwest Cay) and parts of Turneffe we couldn't take the route across the middle of turneffe, same with the inside route between Belize City and San Pedro we barely fit through those 2 islands halfway between and that was at 30 knots, we had .6-.8 feet for 100 yards. But any of the yachts mentioned will serve the purpose AND the Hatteras' are very comfortable. Also, compared to any accomodations in Belize, any yacht you buy will be considered The Ritz Carlton.

60' Hatts run down to Trinidad, Grenada and Venezuala every year. Not a problem.