The cage is bolted to the body in 18 locations on the interior and indirectly to the rocker area in 4 more and now 2 more points from the firewall down to the frame. The firewall points do tie into the interior cage with short tubes that connect to the A pillar tubes at dash level. The 4 points in the bed (pics at post 12) bolt through the original body mounts and help spread the stress of the somewhat flimsy bed floor through to the whole structure.
Their are 4 bolts at the windshield frame, (original top mounting holes) 2 points at the back of the bed, 4 points in the bed floor (body mounts) 2 points at the front of the bed (also tied to the frame), 2 points at the A pillar tubes, 2 points at the seat tubes (tied to the frame with A pillar mounts) and 2 points on the firewall.
Also keep in mind their is a 2 inch square tube that runs through the rockers that the nerf bars bolt too and also the body to frame tubes bolt too as well. (pics on posts 16 and 17) So the body is stiffened considerably in the rocker and door pillar area which is quite important when the rocker boxes are cut out. All of this structure allow the nerf bars to easily handle all of the weight of the Blazer without any problems while keeping a stock appearance and only adding a small amount of weight.
The idea with a solid mounted cage and a rubber mounted body is to let the cage provide additional structure to not only the body but also the frame, but let the body "float" somewhat and not receive a lot of stress fighting the both the frame and the cage.
exactly what my blazer wants to be when it grows up! 
Always a deadline looming.....I guess that's the bad thing about choosing a career that's the same as my hobby.
