Smartphones support gaming, social networking, real-time communication, and individualized experiences. Children and parents often take part in digital experiences with distant friends while isolating themselves from co-present family members. We present MeteorQuest, which is a mobile social game system aimed to bring the family together for location specific game experiences through physical play. The system supports group navigation by mapping screen brightness to the proximity to various ingame targets. Mini-game stages were designed together with interaction designers to encourage physical and social interaction between the players through group puzzles, physical challenges of dexterity and proxemics play. We conducted an exploratory study with three families to gain insights into how families respond to mobile social game features. We studied their socio-spatial arrangements during play and navigation using the lens of proxemics play and provide implications for the design of proxemic interactions and play experiences with families.