Uh Guys,
Before you get too carried away the sheet metal on our 4Runners, including the hood, is a structural component. Here's how:
Hood - While not designed to carry any load, it is integral in a front end collision as it is designed to fold and offer resistance to the incoming force of whatever you hit (or hits you)
Fenders, Doors Quarter Panels and Roof- Sheetmetal "skin" is attached to door frame by welds and adhesive to stiffeners which will hold them together during a side impact, causing them to act together to resist bending in an impact.
Imagine driving your 4Runner around with no sheetmetal, just the inner stiffeners, and getting hit. Yes, the sheetmetal plays an integral part of the vehicle's structure.
Thickness of the metal is not as important as the rigidity of the metal, which is accomplished through metallurgy and what we usually think of as "creases" or "curves" of the sheetmetal. Ever wonder why a panel is not perfectly flat on any vehicle?
And finally, hail damage. I have seen hail dent a fire truck hood and break plywood. 1/4" steel plate is what you need to be impervious to hail.