Do you already own the toolbox? If not, most of us who tow 5th wheels use a below-the-rails toolbox that mounts on the floor of the bed. You'll find that, with most new trucks with higher bedrails, every inch of 5th wheel-to-bedrail clearance is critical, and the situation that will get you is the sharp turn through a depression onto a hill. Been there, done that, got the t-shirt (and the bill from the body $hop) many years ago.
2016 Ram Longhorn 3500 Dually 4x4 CCLB, 385/900 Cummins, Aisin AS69RC, 4.10
2014.5 DRV Mobile Suites 38RSSA #6972
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