I just drove from 5k miles GA to AK and the Alaska Highway towing a Ford Focus on an American Car Dolly. I installed a Protect-a-Tow before leaving. I started using and set up the Protect a Tow after entering Canada and roads started deteriorating for the last half of the trip. I also put Reflectix across the toad windshield for additional protection
There are many unpaved stretches along this route but for the most part the Protect-a- Tow did the job. Yes a few pebbles (maybe 5 penny sized) were found lying on the wiper blades and on the airfoil on the trunk of the toad when we arrived in Anchorage. No significant damage or scratching of the vehicle. I can't say if the pebbles were thrown from side passing vehicles (protect a tow could do nothing for them) or thrown up from the dualies on the moho.The reflectix combination made a difference.
My moho exhaust is to the side so not a problem, but the rear facing generator exhaust was a problem. My fix was a small metal shield I fabricated on the rear bumper in a semi circle (4" dia?) around the genny exhaust. I bring the Protect a Tow in and attached below the shield. Works great- no problems
I'm pretty pleased with the Protect a Tow set up.