Valentine~ requested Moon Island minus the hill in the middle with a few extra roads. And here it is! I've included a pic with a 2x2 lot just to give you a rough idea of the road sizes.

http://i73.photobucket.com/albums/i239/ktheartilly/snapshot_0000000c_74d813bd.jpgInstallation: Extract file to Documents/eagames/thesims2/sc4terrains
Load game and create new neighborhood, finding the new file.
For neighborhood preview, either take your own picture or use one I've attached. Open it in paint, and save as a .png file. Go to documents/eagames/thesims2/neighborhoods. (Do this after creating your new neighborhood).
Find the picture with green lines all over in, and replace it with your new pic, giving it the same name, (ie. NXXX_Neighborhood). Load the game, and your pic will appear in the neighborhood preview.