I often find Growth and Approach difficult to figure out without first establishing the domains. At first, I was leaning toward Do-er, lines like, “What is it you want me to do, Zoe?” We also see Mitchell running in and out of homes to get contracts, taking notes, filming the bus, buying Nicole presents, etc.
But maybe underneath all those actions, Mitchell is trying to be the kind of person he thinks he needs to be in order to win over the townspeople. Even his mannerisms change with each group of people he meets – snickering with the motel owners, kneeling with the hippies, informal with Nicole and her father, stern with Billy. With Zoe, he’s tries everything to be the best father he can be. Maybe the line that reveals Mitchell’s approach the best is when he tells Billy, “Let me direct your rage.” Mitchell wants to be a channel for others, a surrogate for others who’d express his own anger.
I think @Alejandro’s right with Start as well. Only, I think we’re waiting for Mitchell to hang up the phone and turn his back on Zoe. There’s nothing he can do for her. She’s a lost cause. The solution is to give up & walk away, much like the townspeople.