UNZAN BROFIST BUMPER CARS. PLEASE.
Of course there should be several meet-and-greet areas for specific locations.
Actually, I think a park that's mainly just an abbreviated replica of Gensokyo would be friggin amazing.
They could do it Disney world style where there's different areas, each belonging to a different part of Gensokyo. Each place could have it's own cute souvenirs and maybe a specialty food, like Epcot.
Hakurei Shrine would serve ocha that you could drink with a Reimu cosplayer.
HOLY POOP, maybe at a certain point each day an incident will happen

And the characters involved will do a stage show!
OH GOD PLEASE UNIVERSE MAKE THIS HAPPEN.