The only problem we had in 12,050 miles was a rock chip. I had no extra protection. I found that the folks up north have the same vehicles that we have in the lower forty eight and they don't want them destroyed any more than we do. They have developed a way of avoiding rock chip, it is called, "Slow Down and Move as far right as you can without throwing rocks from the shoulder".
Think about a guy with a semi, 2 to 5 hundred thousand, windshield as big as most RVs and custom paint jobs. They see you and if you watch they slow down and move to the right. I usually slow and move right when we separated by about a hundred yards.
For the most parts, they are great drivers up there.
The bug screen is a good idea though.