He would have to wait.
Downstairs in Olivia's nest the baby possum were just beginning to explore life outside mom's pouch, no farther than her back, of course, but it was a start. As Rachel headed down the tree with her four babies right behind her, she stopped to tell Olivia to keep an eye on Caleb, because he wasn't able to manage the climb just yet. Rachel had told Caleb she loved him so much, and someday soon just the two of them would go on his first trip, but she was worried because he looked so sad.
While everyone was gone Caleb got to thinking, "I'm always too small for everything and I never get to go anywhere, but I'm not too small to be a possum, and then I would get to go everywhere."