Traditional location-based puzzle games (LBPGs), paper-based or digital, often limit interactive engagement and tangible expression. To explore richer interactions, we conducted a design workshop investigating tangible user interfaces (TUIs), yielding a key insight: reimagining the printed circuit board (PCB) not merely as a hidden component, but as a unified medium merging circuitry and interface. We materialized this into Pin City Book, a PCB-based TUI platform with modular electronic boards, customizable maps, and auxiliary components, demonstrating its versatility through Skyline Traveler. Evaluations with players (N=28) confirmed enhanced enjoyment, environmental understanding, and social engagement; a study with developers (N=15) validated its feasibility, accessibility, and extensibility. Our work contributes a novel platform and advocates for PCB as a promising TUI medium, bridging aesthetic form, electronic function, and maker accessibility.