its save to say that you will need to write something on your own
Tiled/tmx is not what you need here, you want customized stuff, plus the streaming...
I always write my own level editors.
This is our old one, working on a new one though, since this was still for slick and was never 100% ported to libgdx:http://www.youtube.com/v/Vyl-B7aULOo?version=3&hl=en_US&start=
as for streaming, well, this is a tough one. But an obvious one.
I have never done a continuously streaming world ala GTA, but I was always intrigued to make one.
So lets have some other people comment that may have some experience