How much is "quite a grade"? As Pat said, should be doable. I would suggest getting a PAIR of Rotochoks to lock the wheels AFTER you place a chock of suitable size in front of the both wheels, and let the truck/trailer roll into the chocks. Be sure the trailer can't roll forward even a little bit before lifting off the hitch. Some hitches can be hard to unlatch if the trailer is pushing into or pulling back from the tow vehicle.
Joe