I have posted about spare tires on this blog and on various RV forums.
One thing almost no one considers when shopping for a new RV is the potential need for a spare tire. After all, lights in the ceiling seem to be more important to many as is having 3 televisions
The assumption that having "Roadside Assistance"policy is good enough, many times does not work as well as the advertisement.
Competent truck tire service centers have the ability to change tires at the side of the road but it appears that the insurance companies (ones selling the idea of assistance) are really only knowledgable about cars.
I have suggested that if you don't have a spare you should be able to get a used tire, in your brand, type and size and find some way to carry it around. Used tires should cost closer to $50 for 22.5 sizes and if you know a fellow RV owner who is getting new tires I bet you can make a deal.
Having a tire only, would allow a regular truck tire service truck to come out, mount, inflate and change the tire. You still will need a new tire but you should be able to get a better price on a new tire somewhere in the next couple days when you have time to do some shopping around.
Your "old" spare tire should be thoroughly inspected but should be OK for a few hundred miles at 55 mph max on a rear dual position.