I haven't seen ANY of the story pack sized sets in the USA except for the first two that made up wave 1: Pinkie Pie and Sweetie Belle's Sweet Shop and Fluttershy's Nursery Tree.
I have never seen Rainbow Dash's Camping Trip, Fun at the Fair, Cheerilee's Picnic, or Sweet Slumbers with Star Dreams on physical shelves in the USA, though I was able to get Camping Trip and Fun at the Fair from the Hasbro website a while ago. Sweet Slumbers is listed on the Hasbro website but you can't actually order it there, so that's fun. I'd love to have Star Dreams.