I learned that one the hard way. While still in my late 30's I was ridding from Nashville TN to Roanoke VA in a day using the Blue Ridge Parkway some of the way. It was about 800 miles at that point on a Road King with a windshield, seat bags and some extra size hard saddle bags. I rolled into Roanoke about 5pm thinking Natural Bridge and Luray Caverns was my stop for tomorrow morning before continuing on to Gettysburg to visit my family. It was just 100 miles more and I had sunlight until at least 8:30pm. So I stopped for gas. Going through the mountains of Tennessee the whole way they allow full length double trailers (Not the 2/3rds length ones like most places) on their roads. I would feel the buffeting a mile or more away from the truck. When I got off the bike in Roanoke and tried to pull the key out of the ignition to open the gas cap my hands were shaking so bad I kept dropping or tossing the key. The guy over at another pump offered assistance and I got the bike filled up. I decided to bag the extra 100 miles that evening and found a Brand new motel and restaurant right next to the gas station.
I few years latter I road a Goldwing back from Texas to S. Florida for a friend. I did 1100 miles that day and didn't even feel it due to the frame mounted faring and good aerodynamics. I was also about 10 years older, and I was able to make the ride in one day where I had planned for three 400 mile days. No issues putting gas in on that bike from being beat up during the ride. I've also done about 800 miles on a Road Glide which is basically a RoadKing with a frame mounted faring and lowers and a mount for a tail bag. Very nice down the road for trips even two up. Frame mounted is the only way to go.