I'm probably "on the clock" about 45 hours per week - I try to do about 8 hours a day but I go over more often than not. But maybe only about 25-35 hours of that is focused work, using a relatively loose sense of "focused" (not doing something blatantly non-work, like reading Twitter or walking around outside). I think my work output is constrained by energy levels, not clock time, so I don't really worry about working longer hours or trying to stay more focused, but I do try to optimize work tasks and non-work errands to reduce their mental burdens.

I think the benefits of living in a hub city (SF, NYC, Boston, or DC) are very large and are well worth the higher costs, assuming it's financially feasible at all, especially if you currently have no personal network in any city. You'll have easy access to interesting and like-minded people, which will have many many diffuse impact and personal benefits.

Also, those are probably the only American cities besides maybe Chicago and Philly where's it is easy to live without a car (and arguably it's only NYC). 

What makes someone good at AI safety work? How does he get feedback on whether his work is useful, makes sense, etc?