That looks pretty promisiong. Are you planning on having a basic road piece that you fill out with random buildings? Or are you trying for a semi-random street plan? Regardless, I think it's a good start. Keep it up.
Also, keep dropship and UFO tiles in mind. Especially the big UFOs can get really spacious... We don't have a Battleship tile yet, but you can assume it's no longer than the Bomber (though maybe it'll be wider). You'll have to either provide for assemblies that can take them, or restrict your RMA to smaller UFO types. Obviously, the former is preferrable.