Your opinion may differ:
Based on experience with a 5.4 Expedition and a 2012 6.2 gas F-350, your're going to be VERY disappointed trying to pull more than 7,000 lb. with a 5.4 engine, even though Ford rates your truck at 9,000 - 10,000 lb depending on truck configuration. You're are going to spend a lot of time in 3rd and 4th gear spinning at high RPMs. For what you are looking at, you need either a 6.8 engine in an older truck or a 6.2 in a newer truck. The 6.2 comes with a 6 speed transmission with close upper ratios which are great for towing.
Depending on the nose design, a fifth wheel may be as efficient at highway speed (where wind resistance is a HUGE factor) as a bumper pull trailer. It depends on the design of the two trailers compared.
Len R.