Long before Al's awesome breaking news that the next ride project for DCA will be a Monsters' Door Coaster, there was a rumor that two smaller attractions would be built in Cars Land, along with a Sci-Fi Drive-In. I'm envisioning two attractions as follows:
1) Tugboatopia - A combination dark ride, and trackless Cars version of Disney Sea Aquatopia. Like Crush's Coaster at Walt Disney Studios Park, the dark ride would incorporat a "wet for dry" environment. The trackless segment would utilize an actual water environment (as w/ Aquatopia) w/ various rocks and other objects to dodge. The vehicles would also function as "bumperboats".
2) Trev's Freight Train Coaster. A moderate sized swivel coaster like the Seven dwarfs Mine Train. Train would travel thru industrial area of Radiator Springs, and thru a building (dark ride section) where agricultural products are being processed.