I look to Joanne Fritz at My Brain on Books for the scoop on all things Middle Grade. Not only does she review and recommend a never-ending stream of great books, she also works as a bookseller. She has incredible insight into the biz.
If you're not following her, you should be.
Just last week she focused on a few books with moving as a theme. I was able to get one from my library right away: Turtle in Paradise by Jennifer Holm
Tiny synopsis: It's 1935. When Turtle's mom takes a new job, Turtle is sent to live with extended family in the Florida Keys. Falling into the pattern of life in the Keys is an adjustment. Turtle has to get along with family she never knew she had, get her bearings, try to fit in, and maybe find a little pirate's treasure, too.
I loved this story. I find myself connecting more with MG that's set in the past (I'm thinking about The Evolution of Calpurnia Tate). Eleven year old Turtle, the anti-Shirley Temple, is such a great narrator. She's world-weary, stubborn, and tough. The setting is so Our Gang-- kids being neighborhood kids back when you could spend your whole summer outside without fearing for kidnappers or pedophiles. The kids are hilarious- her cousins are downright mean, and Turtle gives just as good as she gets.
You get to discover the Keys along with her, including local characters and her own family. It's fantastic.
Pick this one up-- it's worth it.