I am a full timer and I have only needed roadside assistance in 17 years twice. Both times Good Sam has come to the rescue (towing in both cases). I have never paid a dime and I was towed to the exact facility I requested (I found the service center before I called for a tow).
I have a heavy RV which requires special trucks to lift and tow and we have not been left stranded by Good Sam.
Tires can be a separate issue depending on the type of tire your coach requires. If it's something unique like I use, I would carry a spare unless you have a tag axle coach where you could steal a tire to allow you to limp to a nearby tire center.