Use twice as many bolts. Use stainless bolts AND nylon plastic washers under the bolt and nut. Rhino line your bed first for extra durability.
Aside from a few weak spots, the Al body is much tougher than the steel one was. I slid off a snow and ice trail into a tree recently. Should have completely destroyed my right quarter panel. Scratches only where flares will cover. And pin striping on my door and badge. No dents, no folds. VERY impressive. Remember GM ragging on Ford's choice of upgrading to aluminum? GM is retarded.
4 years now in the saltbelt. Not a single spot of corrosion.