Best check the boat out, mate.
When you go over to the dark side you risk more than your soul.
Take a slow stroll down the north coasts of PR
and DR and you'll see what I mean about few places to stop. There are probably a few places you could put in, but you're not going to find many marine tradesmen on the dock.
If you're concerned about the 250 nm on your second or third day out in a new (to you) boat, you might consider bumping along the south coast of Puerto Rico, where there are a few more places to stop, seek shelter, fuel and mechanical assistance should you need it. You can also stop in Samana, in the DR, which breaks the trip somewhat, but here you have the same issues with DR officialdom I referred to in my original post. I haven't done with the south coast of PR
or been anywhere in the DR except Ocean World and Luperon, but have heard of many boats that have stopped in Samana.
If it's any consolation, the US Coast Guard is very active in this part of the world and if you get into deep do-do (i.e. lose the engines altogether) you can probably expect someone to come to your assistance. I'm not sure I'd want to have a break down in some small DR port as it can be expensive and time consuming to get parts through customs. Better to be absolutely confident in the engine(s) before you start -- either that or ship it to FL.
How big is this boat?