A Thousand Tomorrows was one of my favorite Kingsbury books. I was quite excited to find out there was a sequel. Just Beyond the Clouds focuses on Cody's return home and his relationship with his brother Carl Joseph, who has Down Syndrome. Carl Joseph has been attending a a program that teaches him the skills he needs to lead a more independent lifestyle. This comes as quite a shock to Cody who has a very old school mentality on just what it is that Carl Joseph can and can't do. This was the most interesting part of the story for me.
I do suggest you read these books in order. Though you could read this one and understand who the characters are, I do believe that that the books are better read together and that A Thousand Tomorrows is the better of the two books.