Astrid & Apollo and the Starry Campout by V.T. Bidania
From Picture Window Books:
Astrid is afraid of the dark and doesn't want to go on her family camping trip. But her twin brother, Apollo, is excited. When they encounter scary things such as crawly bugs and the creepy dark, Apollo helps his twin through them. And when they encounter the scariest thing of all, Astrid might just be the one to save the starry campout.