Sounds like what you really need is a better roadside assistance. I've got FMCA, and when we broke down 40 miles west of Needles.CA, it only took them 45 minutes to get a truck to us, and cost me nothing extra for the 80 mile tow to Kingman.
I'm not a DP, I'm a 37' gasser, but they sent a big enough truck that they could have towed a Prevost , had I been in one.
I've heard of stories where people could get their truck towed but the company had no way to tow the trailer. In fact, one of my hosts last year towed his rig to Reno to trade it in. On the way back to the campground, his truck spit the driveshaft out. The CHP called me to find out if I had some way to drag the brand-new trailer off the road, because the tow company couldn't handle both the truck and trailer. Luckily, he bought a bumper pull. I was able to take the company truck and retrieve his trailer. If it had been a 5th wheel, I'm not sure what they would have done.