Getting gold rings in all Thomasville Playground Challenges are not required for this achievement nor regular 100% completion, any ring is valid (and Thank God for that because getting gold rings in these events are a pain.)
Thomasville Playground is a open world-esque mode based off Thomasville (a location from the 3rd movie) where you can practice your trick and driving skills, as well as completing a few challenges, the challenges involve destroying explosive boxes within a time limit, throwing balls at explosives, popping balloons, etc. Depending on how you do in the event before the time limit, you get either a bronze ring, a silver ring or a gold ring, get any of these rings in all challenges and you'll get the achievement.
There's also a few multiplayer challenges you can do on Thomasville Playground, this game only has couch co-op, so you'll need a second controller. I'm not sure if the multiplayer challenges are required for this achievement, but you'll need to play them to get a few Skill Checks, same with all other challenges in Thomasville, so you might as well get a second controller for these.
You'll also find hats around Thomasville, if you collect them all, you'll unlock Mack as a playable character and another achievement, check the guide on that achievement if you're having trouble with them.