>>112776778Here's your plot:
The reason Sonic is on a roadtrip is because that bag he's carrying in a few trailers is full of his ring portals and he lost them by tossing the bag through a portal to San Francisco and he has no sense of direction to actually get there since he's unfamiliar with Earth
Movie ends with Sonic using his last ring to trap Robotnik on his old homeworld while he stays on Earth; thinking he's no threat to his world without his tech.
Post-credits scene is Jim Carrey in the full mustache somewhere in Mushroom Hill Zone