According to what I've read in ATA (Ask the admin) about 2-3 weeks earlier, the homes can be put into any of the four towns in the future and they will have neighbourhoods too. But they continue the three remaining cities next year. I quote some of the bits (most of them are from codemonkey37179 developer):
Q: Question #2: What is Towns 2? Why was it made?
A: Towns 2 is the replacement for Towns. We made it because the old code for Towns was not maintainable and by making a new towns we are able to create more elaborate events. We held the Rejected Olympics in Towns 2. We are adding all the towns, though currently we only have part of Gambino. We plan to add a lot of new features, and bring (almost) all the old features from Towns.
We are hoping to have the houses in by the end of this year, as well as bugs, shaking trees, etc.
Then at the start of next year, we start adding the next town (Barton, Akea, or Durem). We have not decided which one.
So I guess Isle de Gambino will be fully finished first... He also mentioned there would be a "GPS device" with which you can find your friend (maybe similiar to the one in zOMG).