What process does Christopher use to decide where to go next?

He decides that going to live with Mother in London was the best option. He knocks on Mrs Alexander's door and asks her to look after Toby, and tells her where he is going and why. Mrs Alexander tries to persuade him to come in and talk, and she suggests ringing his father. Christopher runs away, breaking into his own house. After picking up enough provisions for himself and Toby, he sets off for the train to London.