The park's pond can be clearly seen in rides 2, 33 and 68. Aichi frequently visits this location when depressed or needing to think through recent events.
Fuchū has a primarily service-oriented economy, which makes it an ideal location for a merchandise-based anime like Vanguard. It would not be at all difficult to imagine Card Capital having set up shop here. Ironically, the store that Card Capital is based on is actually located in Akihabara.
(via vg_akira, matibari)