Moving the blue boy downhill, away from the trailer, and using a longer hose, will take care of the height problem.
I carry a 25' blue hose for this purpose, and use it only for draining gray water.
I use a 10 gallon tote for both of my trailers. About 85 lbs when full is more that I want to pickup and load on the truck.
If you decide to use a longer hose, remember it will not drain well unless the second inlet to the blue boy is open so that it will vent as water flows in.
2014 Silverado LTZ 1500 Crew Cab 5.3L maximum trailering package