Assuming your RV is a dually, you may have the choice to run single or dual chains on the back. (Depends on the amount of room between the tires...) If there isn't much room, your only choice are the dually chains that have links that span over both tires with no center chain.
I have run both single and dually chains on my big dump truck in the winter for plowing. The single chains on the outer tire were FAR easier to install, and I never got stuck with them, but I did struggle a few times. Going to actual dually chains on both tires made it virtually unstoppable, but they are HEAVY and 4x harder to install... Putting chains on the rear of an RV that's fairly low, and has tight wheel openings will be a chore.
For offroad use to assist getting out of clay surface roads common in the desert SW after a rain, your best bet would be a light set of simple set of laddar chains. "Heavy Duty" chains are probably not necessary, and the lighter chains will be much easier to store and install. Honestly, single chains would be my preference IF there is room between the duals to install them... One of my buds has a set of cable chains that he finds sufficient for his needs on a Tiger camper. Sure, real chains are FAR better performance-wise, but the cable chains are very light, take up less room, are easier to install, and they still get him out of "sticky" situations when he gets surprised by some snow or rain on back roads. They do not hold up to any level of abuse, but if you have limited clearance between the duals, you might still be able to run a set of cable chains on just the outer dual. They also tend to do less damage if a cross cable breaks.
If you want to try a set of real chains, I have a new set of dually chains that I will give you if you are in the desert SW and can come to Cortez Colorado. Been trying to sell them for two years but evidently nobody runs 215 or 225 tires on their dually anymore...
If you RV is not a dually, the diamond pattern chains are my go-to. I LOVE them, and use them on the back of my plow truck. I plow an HOA with 10 miles of roads at 7000' in SW CO. They have LOTS of miles on them with no issues, and hardly any wear. Most of the diamond chains actually self-tighten as you drive too, which is nice.
FWIW, my experience is that Bungee tensioners on chains are always a really bad idea. Tighten the chains when you install them. Drive a couple hundred feet. Tighten them again. Repeat until they no longer loosen. THAT is how you install chains. Bungee cords will not hold the chains tight over about 15mph. Fine for a tractor perhaps, but not cool for road use IMO/E.