These are the episodes that I would add. Because in my opinion. Nickelodeon really needs to make more of these.

Middle School is finally over, and Dipper and Mabel are itching to get back to Gravity Falls. They're only unsure about one thing: Bill has returned over the school year and is getting ever closer to being able to truly return. Join the Mystery Twins, along with their friends, family, and someone new, on their new adventure as they go through the second summer in Gravity Falls.