Makes sense to me. I did this instead of putting the torque boxes back in. http://www.cardomain.com/ride/2200206/5
That is exactly the same location where my front cage uprights exist and I am also putting in an extra crossemember to act as an outrigger. You can see how close the torque box is to that area and how easy it would be to tie it right in somehow. That's what I'm figuring on doing. Your's is a bit more rusted through than mine.
Yeah, if they hadn't rusted to nothing, I would have done the same thing you're doing. The cage would have fit better if I would have moved it about 4 inches forward and tied it into the torque boxes instead of the outriggers. I think it'll work though.