Here's the passage from my book that references it:
Today’s Kerouaction: On Livelihoods
A beat policeman? This seeming paradox – someone who typifies the “anti-establishment” lifestyle becoming a law enforcement type – indeed tells us that it is okay to use the system to beat it. That is, if money is a necessary strategy for doing those things you want to do, and you are at a point where doing something beat to earn money is not happening, it’s okay to earn money doing pretty much anything. Even being a policeman. I bet Kerouac looked at it as a necessary evil, an ironic act, a way to take advantage of the system. So if you can earn a living writing or playing music, go for it. If you can’t, consider homelessness and mooching. As a last resort, get a job. Any kind will do as long as you don’t let it kill your soul.
Make a list of five ideal beat jobs. Find a newspaper and see if any listings match entries on your list.