Last month we posted about a new book listing on Hatchett's Website talking about a roadtrip storyline, with a release date way out in July of 2019. The description and listing has since changed, hinting even more that this might actually be based on a brand new episode, rather than Road to Friendship. It's still pretty vague, but it includes the full mane 6:
Description:
Let's hit the road! Join the Mane 6 on a special My Little Pony event in this exciting leveled reader!
The release date has also been bumped up to June 25th, a week earlier than previous. Hopefully more information arrives soon. It could just be a one-off adventure, but most of these are based on episodes.
Thanks to Astral Phoenix for sending it.