Are talking about touring in America? It all depends on where you are.

In general, it's like other kinds of vegan travel. You will probably have decent restaurant options in cities, in small towns, maybe not. If you have cooking gear it's fairly easy to get by as long as you have decent access to food. In the northeast US it's easy, supermarkets are everywhere.

It varies by country. I toured for 8 months in South America recently. It is very, very difficult to be vegetarian, and harder to be vegan there. I rarely ate in restaurants, except for in major cities (Lima, Quito, Santiago) where vegetarian restaurants existed. I cooked my own dinner almost every night. In many rural places, there was almost no produce, like southern patagonia, where nothing really grows. They eat sheep. Still, I managed, I ate lots of pasta, potatoes, breads, jam, that sort of thing.

The hardest thing about being vegan and touring is turning down food. Depending where you are, it is fairly common to be invited into someone's home for a meal. It's hard to turn down the kindness of strangers. I think I would have stayed with more families in small villages in South America, if I wasn't worried about insulting them by turning down food. You also miss out on a lot of cultural exchanges, people like to talk about food. That's life as a vegan in general, but I find I notice it a lot more when I'm traveling.