Aloha and welcome aboard!
Only you can answer the what boat question. Start looking at all the marinas
for boats for sale
and talk your way aboard each and see what fits you best. You'll need something with a reliable engine
or engines and something with enough fuel
tankage to take you where you want to go.
Start taking some boating classes
if you haven't already.
You can take as long as you like to make the trip but you have to figure the speed of the boat and how many nautical miles it is from where you are, along your preferred water route
and how fast your boat (that you haven't chosen yet) can average.
Start reading books
in your public library about boat designs and about boating