We did the Yukon and Alaska Highway back in 1992 for the 50th anniversary when there was a lot more gravel compared to present day. I put a piece of plywood on top of the front lower section of the 5th wheel to protect it from rock hits coming off the truck tires, it did a good job but the front cap took a couple of hits up high from passing vehicles. Pull over as far as you can and slow down when a passing vehicle approaches, it will cut down on the damage.
I saw a class "A" with a full plexiglass front installed to prevent damage and I talked to an Airstream owner who was going to have the front re-skinned when he got back home!
2013 Redwood 36RL, 2011 F-450, Sat Internet, Sat TV