This paper studies how hukou-based education wedges and child-arrangement costs jointly shape welfare and intergenerational educational mobility in China. I develop a quantitative spatial model with overlapping generations in which households sequentially choose education, migration, and child arrangement, and estimate it using census and household-survey data. Under a common financing rule, two child-targeted policies raise the co-migration rate to a similar extent but differ sharply in welfare and mobility. Subsidizing co-migrating families in high-cost destinations generates 1.4 times as much welfare per unit of government revenue as removing migrant children’s education-access wedges. These gains concentrate on recipients. Removing the education-access wedges delivers over four times the mobility gain per unit of revenue, and the resulting human capital generates growing welfare gains across generations. A broader reform that equalizes public-service access for all migrants is the most welfare-efficient but does not raise mobility.