Easiest way to sum it up: Seacrest County, but not an exact duplicate.
Thing is, I would absolutely love a map where there is a nice beautifly pieced together terrain, with either extremely smooth roads to prevent your vehicle bouncing randomly or a interior for the roads, which is also smooth enough to prevent torque from loving up your jeep off the sides.
Mind you, to build this with bricks, your jeep would end up going all herpderp on you
Also, it doesn't need to be as graphical as Seacrest County itself, but I'm sure you knew that.