Hi Chas,
I saw your post through a different thread, I never caught this on, I skipped it by for some reason.
Dirty Linen is probably the best site for US/Canada fests. If you're planning hitting the Northeast US. There's the Getaway in early Oct, the Portsmouth Maritime fest late Sept (you can combine those. There the Mystic Seaport Maritime Music fest on June 10 -14. There's the Old Songs Fest June 26 - 28, again you could combine.
You thread title may have missed the attention of us here in North America, it' wasn't very specific & looks as if you were performing on tour & advertising instead of asking about planning traveling plans. Maybe a retitle would help uyou out more. You'd be more than welcome though if you plan on New England. I looked for some site that would be inclusive of US folk festivals but aside from Dirty Linen nothing very helpful came up. Maybe others have found somthing better but I can't. To me it looked like you have to go to individual festival sites.

Good luck Chaz

Barry