A spare tire is just not worth the bother. I have been RVing since the mid 80's and have logged over 200,000 miles, have RVed to Alaska and Mexico and only had one blowout, and that was due to a 20 yr old tire an unscrupulous dealer stuck on the inside dual.
Check your tires before every trip, replace them around the 7 yr mark and your odds of needing a spare are nil. If the odds are against you and you have a problem, due as mentioned above, make a phone call.
Think about it....I can't remember even using a spare on any of my other vehicles.