[s1artibartfast]

I would look at land in northern California and build a rustic cottage. Depending on how close to the sea you want, you should be able to find a an acre or two for 5OK. The other 50k would cover the cottage, a nice deck, and wood fired hot tub.

Certainly a project, but if you are into that sort of thing, it is half the fun.

My main consideration would be drivable access from the bay area, but your constraints may differ. If I need a plane to go there, I am unlikely to visit frequently.

[quickthrowman]

50k will barely cover sitework and utilities after buying the land, unless you plan on not having electricity/water/sewer or car access

[s1artibartfast]

Indeed. I did not include City hookups in my concept of a rustic cabin. In fact, I was thinking of something specifically outside a city.

I was thinking more along the lines of off-grid and unpermitted which is doable for 50K