In the novel, The Children’s Crusade, how does Penny withdraw from her family over time?

In order to give herself some space from her children, Penny asks Bill to allow her to set up a storage shed as an art studio where could enjoy her creativity. As time went by she began spending more and more time there until she eventually began sleeping there. When the children become young adults, she slowly began a move to Taos where she started taking classes there. At first, the classes lasted a week, then a month, then the whole summer. Eventually, Penny leaves her family completely and moves to Taos where she supports herself with her art work.