I think our node pathing could be of use in this scenario. It is very easy to use and set up. You could specify different regions as checkpoints and even include shortcut paths depending on the way gameplay works. I havent worked on any car controllers but im sure it wouldnt be to hard to control the movement of the veichles to produce minute subtleties in turns and such.
https://forums.unrealengine.com/showthread.php?99384-SUBMITTED-PLUGIN-Region-Pathing-Advanced-Node-Traversal