Not one to take the easy path, eh? Try some tactics authors use when they have two protagonists with separate storylines for much of the book: 1) Give the characters equal screen time, with their chapters appearing in a regular sequence. 2) Keep the chapters short so readers won’t think you’ve abandoned a character for too long. 3) Transition out of one character’s chapter and into another with a common element. For example, end a chapter with Character A climbing onto a bus with resolve, and start the next chapter with Character B climbing down from her treehouse with resolve. This will create a sense of continuity. You don’t want readers feeling like you’re jumping from character to character.