When slavery was abolished and the slaves were "free" to go, they tried this. I know of one town here in Colorado that was established for that reason. Of course the laws were more restrictive then but it is virtually the same. The town did thrive for awhile but crashed miserably after several years (*part was the economy and part was the weather so it wasn't just the isolation).
I don't see this as working for the TG community though. Are we to assume it is only Ts? Then when someone decides to not dress, would they stay there? What about spouses. Do we assume that every person there is attracted to Ts? What exactly would be the economic stimulus? I would guess that in your scenario it would be a broad based population where every job was covered? That would have to be a huge town then.
This sounds more like a fantasy camp than a real town. Consider that the majority, if we believe the posts on this site, of CDs, don't want to dress full time and many swap back and forth quickly.
Would I live there? No. It smacks of segregation even if self imposed.