I would love carsland to be built in full, and at DHS it would fit perfect.
I think though, keep or move LMA but get rid of the backlot, build carsland there, and incorporate LMA into it somehow.
They could make it a stunt show with the cars characters.macqueen is already featured anyway.
It would add a whole new experience to a stunt show I think.
the road to radiator springs could even continue the streets of america road, giving the feel that your leaving the city on the mother road and come across radiator springs.