I took about a year off, in the end... I began by reading and running... I ran a few ultramarathons, which require 15-25 hours of training per week. I read a lot, particularly intense and complex books that require you to invest the time to actually read them and reflect on them.
In the second half of the year, I ended up traveling quite a bit -- Norway, China, Malaysia, Peru... Mainly to hike, but in every city I tried to set up meetings with startups and businesses to learn what the culture was like around work.
I think I learned more that year than in any year of my life.
[1] https://www.amazon.com/dp/B004ZY23TS/ref=dp-kindle-redirect?...