Greetings, and welcome aboard cool ruler.
I don't think that the Wellcraft 3200
Martinique, with it’s “flatish” modified V
hull, is particularly well suited to the trip. I’d expect she would give you a bit of a pounding, in any seas over 2 - 4 Foot.
The Martinique was built with a 162 gallon
fuel tank. Inboard models, with 320hp MerCruisers,
cruise at about 20–23 knots. I’d expect these engines to burn something on the order of 10 - 12 gph (each), at 20 kt
cruise, which would give LESS than a 200 n.m. range (maybe significantly less, in any kind of seaway!).