Can’t remember book title
So I read this book in 5th grade and I absolutely loved it. It was about this family that goes on a camping trip and the dad has an accident so mom has to leave the kids at the camp site to take dad to the hospital. The brother and 2 sisters eventually leave the site to find their parents. A few details i specifically remember is that the older girl walked with crutches, and that she made her brother promise her chocolate cake and 3 pineapple milkshakes when they find their parents. I remember 2 different book covers, one was the 3 kids standing together in the woods looking frightened. The second had a picture of the boy falling down a steep trail, and the girl in a river struggling to swim. For the life of me I cannot remember the title or authors name. Any help would be appreciated, thank you!!!!!!!