Definition from Wiktionary, the free dictionary
- To travel around the countryside making political speeches etc
- (US) To appear at fairs and carnivals in exhibitions of stunt flying, or sporting events
- (US, of an athletics team) To travel from town to town performing in front of small crowds. 
- 1899, Mark Twain, as cited in 1901, J. B. Pond, Eccentricities of Genius, page 227
- I'm not going to barnstorm the platform any more, but I am glad you have corralled Howells.
- 2005, Marion Elizabeth Rodgers, Mencken: The American Iconoclast, page 109
- It wasn't just the smell of perfumes that assailed his nose every time he entered a stuffy auditorium that he found unwelcome; it was the childish playwriting and barnstorm acting that was driving out the intelligent theatergoer and the production of less commercial plays.
- 2006, Ethan Wolff, Frommer's Irreverent Guide to Manhattan, page 242
- Smaller bands play the clubs ..., while the more established acts barnstorm through New York's surfeit of midsize halls.