There are a number of videos on YouTube of people ferrying small planes across the north Atlantic. Usual route is via Iqaluit, Nunavut on to Greenland.

The hops required to fly over the northern Atlantic are surprisingly small, and quite manageable even in small single engine planes; they're ferried back and forth somewhat "routinely". You might still need ferry tanks, and definitively wear a dry suit while in flight (you don't have time to put it on when you are going down...), and you need a life raft. In case of engine failure, if you (and the life raft) get out of the plane and you get into the life raft within a minute or so, your chances of survival are quite decent. (The cold water will kill you in very short order otherwise.)

You can go Senegal to Recife, Brazil, if you prefer warmer water, but the hops are larger, and there's basically only one island in the middle with a military airport that you can't land on except in an emergency.

The Pacific, in contrast, is this vast ocean (as it were) of water - it's insane. Google Earth shows this beautifully. There's the very northern route via Alaska and Siberia - but while you are over land there, there are virtually no airfields.

Alternatively, you can hop via Hawaii, Marshall Islands, Micronesia, CMNI, Guam, Philippines/Japan, but still, the distances are enormous. And then the South Pacific - look at it in Google Earth. It's just water. Probably better off taking a boat there than a plane :-)