Nice start, an expedition rig is a nice balance between a street an trail, even my rock crawler is more expedition biased due to the anmout of gear I like to bring.
Not sure what square tube you feel needs support from the angle iron in this pic,
But would recommend connecting the front and rear of the sliders,
Dropping onto a rock, or lifting the rig with a hi-lift, could result in the ends being pushed up.
Would also recommend replacing the body mounts, the cab will rattle on the sliders, not that bad on the street, but annoyingly so on fire roads and the trail.
Not too sure what you mean about the body mounts, the sliders aren't touching the body at all, and as far as connecting the front and rear of the sliders, are you talking about welding some tube from the slider to the step-up? or from the slider to the frame?
