How does one make enough money to support oneself while traveling?

As some of you know, in August I am going on a road-trip with an indefinite destination and and indefinite amount of time. While I am traveling, I will need to pay for gas, insurance, food, my phone bill, and I’m sure a few other things.

I intend to sell my crocheted hats while I am on the road. What are some other good ways to generate an income while on the road?