Re: Is there a cheat to smooth terrain in the neighborhood?
Try the create a world tool?
That wouldn't help as that would require a whole new world to be generated.
I'm afraid TS3 doesn't have the cheat present in FreeTime... I guess you'll have to look for a 64x64 lot and bulldoze it for your own use if you're willing to replace said 64x64 lot. Otherwise I don't think there's any other way.