Neal,
you live in Houston, man. Have you ever lived where you'd be isolated for 4 months of the year because of winter? Or where it regularly snows & gets very cold? If not then don't think of it as some kind of paradise before you try it.
I can dig your idea of a lighthouse-house, although I'd probably want to have my lighthouse in the warmer climates. Maybe in the Canary Islands or South China Sea or some nice warm place like that.