Dak,
Seeing your entangled plant, all I can say is this would indeed be an excellent specimen to work upon to create a Bonsai. However, as Majed has rightly pointed out, without seeing the trunk-line it would not be possible to give any suggestion.
But don't get disheartened, not only you could create a great bonsai from the main trunk but also many more interesting bonsai (that would resemble individual specimen) after you cut them off.
You have to make a start somewhere by removing the unwanted thin stems first, and later removing the other stems/branches gradually, once you could get to see the trunk.
Shaukat