I have some map creation programs at home, can't remember the name, but I have feeling they are now free to download.
think I payed about £80 at the time about 4yrs ago. Really good programs though, can create landscapes, and go down in scale layers so can zoom in and out.
It also had a city/Dungeon creator which might be more useful for what you are looking for. Lots of layouts, floor designs and objects to place on it.
Will have a look when I get home and get some details.
Automatically Appended Next Post: This is the company I was talking about
http://www.profantasy.com/
Seems they have got to City Designer version 3, but the first one I have is still pretty dang amazing.
I think the first one is around for free somewhere, or it was, that may have changed now they have new versions. The last time I checked about a year and a half ago it seemed like they where going under.
Glad they didn't and I'll probably upgrade at some point in the future.