All of Gary's suggestions are excellent.
I would only add, as you do when you rent a car, do an initial walk-around noting existing dents & dings and make sure the rental company notes it on the contract before you leave the parking lot.
With an RV, I suggest you do a walk-thru of the interior to note any damage there and have it noted, as well.
We rented a car on a trip to Alaska and waived the windshield insurance, just a few bucks. We had traveled less than 100 miles when a vehicle coming from the opposite direction threw up a rock that cracked the windshield. Since my personal insurance has a $500 deductible, guess who paid for the new windshield. I think the rental firm was charging less than $25 for its insurance... I made a poor decision then, but am all the wiser for it now.