i haven't myself, but i became friends with a chilean couple who traveled around the world according to berry season, Australia, Italy, Germany and so on picking berries, living in free housing while saving for a house back home.
they seemed pretty into the lifestyle, or at least willing to trade a few years for traveling and a house.
yup, it's called the Schengen area:
https://en.m.wikipedia.org/wiki/Schengen_Area
you do not have to be rich to live in Europe, Europe is much cheaper than the states, especially in the situation you're describing as a long-term traveler.