I search around the forum and was surprised to not see this as a topic. Since the day I took delivery on my 2018 Freedom Elite 26HE, I was surprise at the very large opening in the Ford E-350 Bumper. Just behind the bumper is the A/C Cooling radiator just waiting for a rock to do some damage. After our recent trip I did notice quite a bit of grass, gravel and bugs on the radiator itself. This prompted me to do some searching to see if anyone made a product that will screen off the opening and protect the radiator. Google lended a couple of results, but it seems that the products are more for the grill and not the bumper opening.
I did see one website that looked promising - but that site has most of its products sold out. Not sure if they are still in business.