I'm not in a normal city, but have lose neighbors on the sides and my muscovies didn't start laying until July, but it may be she was too young until then. She laid her eggs, went broody, stopped at three weeks (I don't know if something was stealing the eggs, or if she kicked them *all* out of the nest, but they disappeared.), then promptly began laying again and after a few weeks went broody again.
If you live in the city you'll need to clip their wings if you get muscovies, because mine were always flying into the neighbor's back yard until the girls started laying, then the flying stopped. I heard Khaki's are the same way, not that they fly as high or as much as muscovies, but that they stop flying when the start laying. They are rumored to set three nests a year, but as I said, she started late, so I'm thinking just the two this year, and none of them have been fertile so far (I stole a bunch of eggs for the bator, but nothing happened in them). I gave her a bunch of chiken eggs to sit on instead, and she's been really diligent lately, I'll have to kick her off the nest when they get ready to hatch and take the chicken ones so she doesn't kill them (I heard ducks will do that to chicks).
She lays big eggs.... Good luck in your search.