Yeah, you'll want as many cross bars (going from one side of the truck to the other) as you can, I would think. That is probably why most people just do a full-on exo cage, because there is a lot more places to tie things together at.
I'm not sure if you wanted to run a bar into the body, but you could probably tire the corner there by the door handle, into the B pillar pretty easily. Just cut a round hole the same size as the tube, slip the tube in, weld it where it needs to be, then take some silicon, and fill the gap around the sheetmetal/ tube, and then put some touch-up paint over the silicon. That is what one of my buddies did, and it looks really good! It isn't just a hole, it actually flows I guess you would call it.