It’s supposed to be a part of a reimagined frontier land as a whole. My best guess is the old time western feel will be replaced with a more modern aesthetic look of how we view the frontier (think Colorado mountain resort town).
The concept art is based off the animated film planes…the whole concept is about piston peak national forest.
You could argue that riding around recreational vehicles and racing in the wilderness is very much in touch with todays concept of “frontier” , especially for those who live in or around a city and don’t have access to land.
Big thunder mountain will also look more natural within the backdrop of a national forest.