Has anyone bought / rented an old lighthouse, purely to live in? I’m fascinated by the idea - tons of time to read, draw, work on personal projects, etc.
In the US, lighthouses have been sold to private individuals. There's one I know on Cape Cod that's some sort of vacation rental. Apparently the Graves Lighthouse in Boston Harbor is also now privately owned. [1]
A couple points of information that you may know but others may not realize:
1.) Not all lighthouses are particularly isolated. Sure, some have only boat access and have difficult landings--see the Graves. But many are on roads on the mainland or on large islands.
2.) Again the Graves notwithstanding, the lighthouse keeper's house is often a cottage off to the side as opposed to the "lighthouse" itself.
This Old House visited a converted lighthouse in Season 36 Episode 7. They went over all the things you need to do to convert it to a livable space. Long story short, it's expensive and requires a lot of work.
Sadly it doesn't look like that episode is easily accessible.