Issues Getting the Camper Level

Over this past Columbus Day Weekend, we camped at a State Park in Western, NY. All of the sites that were large enough to accommodate our trailer, were listed as having a "slight Grade". This turned out to be an understatement! We were not able to fully level our trailer front to back. We were able to level our camper side to side with our Anderson levelers but this raised one side of the camper nearly 4 inches to get to level. Our trailer is outfitted with a Propride P3 hitch which sits below the frame as seen in the picture and my crude drawing to show its placement. Because of this, we couldn't lower the front of the camper as much as we would have been able to with a conventional hitch. With the jack as far down as we could go, we were still high in the front. My drawing is somewhat exaggerated but wanted to make sure those reading this fully understands what we experienced. I don't know what else we could have done to get our camper level. Any ideas would be appreciated as we have booked a 4 night stay at this same State Park next summer (different site but also lists it as having a "slight Grade"). Thanks!