Some worked on boats and barges for sure. The most important thing to them was the freedom to move.
Theres a lot of difference between Romany travellers (those descended from the original Indian people who went travelling 1000+ years ago) Irish Travellers, German Travellers, both of whom came in large waves to England, and latter day "new age" travellers.
However, saying that, theres a lot of intermarriage. Often, husbands became known by wives names because their families were higher up the pecking order. Often they travelled with relations. Often they took houses in the winter, or camped in one spot for the winter, only to take to the roads in the spring/summer and make their living at horse fairs/ hawking wares in villages/grinders and braziers/hop picking, etc etc.
I think bogga is probably right, it jolted something way down in my memory when I saw what he wrote. Trouble was, I never met the "real true travelling" Grays and Smiths, my mums mum (the Romany line) died when she was only 11 yeas of age of TB, along with most of her sisters. I did get to meet some of the great uncle travellers, and I did know my uncle very well, and he used to go drinking with them all, and work with them and the horses. However, my own nan married a Gorja, and they lived in brick houses, as do I. So my knowledge is far from complete.