An old dictionary definition of hobo is "one who wanders from place to place without a permanent home or a means of livelihood." Historically, the lifestyle of hobos required that they do basic, unskilled manual labor. In today's world that doesn't always have to be the case. Any skill that is in wide demand and does not require an extended time commitment can "work" for the "new hobo." As long as you can advertise your services and earn people's trust (ideally through references) and take their money, you can do anything.
With this in mind, John S. McCain III has set out to become the world standard for hobodom. How did he begin? "First off," as he recounted in his press conference, "I put my affairs in order," my friends, "you know, make sure I was square with the world. So I paid off some debts, put a couple of dollars in my rainy day savings account and made a list of my skills and experience. I guess you'd call this my Plan B. It's serious and very life-altering to be a hobo, you know. Then I went on Jay Leno to announce how I feel about housing in the US."