Getting a boat ready for a trans Atlantic passage takes a long time. I think the idea of buying a boat and spending a few weeks and setting off is shear madness.
There is enormous amount of preparation, from meals, to spares, to sail handling, emergency repairs at sea, navigation, weather routing an communications and so forth. And assuming you are up to it as a sailor you should really know your boat and how to fix it... because you won't be getting help or spares out there. And when you loose one system... how does that impact on the passage. How about losing the self steering or auto pilot? Steering for thousands of miles?? How would rig the boat to steer in lieu of self steering? What do you do when you charging system dies and all your electrics are at risk of becoming useless?
I would work on the boat from where you live... sail it with the right crew (a whole other nightmare) and then have a delivery crew return it or have it shipped back... or sell it.