If it's in Japan, I believe a 1:1 replica of the Shuto expressway and Wangan of Tokyo, with generic Tokyo-esque cityscape with famous Tokyo landmarks like the imperial palace, Budokan, Akihabara, Tokyo tower, etc etc in the middle (and as the base of the Festival) in that area. Once you leave Tokyo, the expressway becomes generic until you come to a fictionalised version of Osaka with the Hanshin expressway and specifically Kanjo lines represented 1:1 with again fictionalised and condensed Osaka in the centre area. In the land between, there'd be mountainous terrain based on the mountains of the Gunma region (featuring touge based on Haruna/Akina, Akagi, Usui, Irohozaka, etc) along with fields and hills and perhaps even a fictionalised Mt Fuji and surrounding forest. And maybe little towns representing Nagoya and Kyoto, along with some villages of the Kanto region. A strong emphasis on Japanese cars of the 70s-90s in the car list.
Another idea is the Scottish Highlands, specifically Glen Coe and Loch Ness, the most iconic and scenic places in Scotland. And perhaps surrounding Glens and Lochs.
And a final idea is Iceland. Featuring lots of volcanic plains and tundra and snow and arctic lakes. with the festival based close to Reykjavík. Maybe even feature an active volcano.