5th wheel hitch question

There is some mis information here that you need to be very careful of. The mega cab bed length is standard short bed, not shorter. Lots of talk about hitches and that was your original question. However with the mega cab payload is going to be your biggest challenge. Look very closely at the two trailers gross weight ratings. I suspect both of them will be either very near or some what over what your trucks cargo capacity actually is. That has always been the biggest negative switch the mega cabs lots of power but way down on payload.