Know the measurements, height, length and tonnage of the RV you are planning to rent. In addition, know the year, model number and manufacturer of the RV. Look it over carefully before you drive it off the lot. Check out every aspect of it inside and out to make sure that there is no previous damage. If there is visible damage, make sure that it is notated in writing on the rental form, so you are not held responsible for these damages upon returning the RV.
Check with your auto insurance carrier to obtain quotes on additional coverage on the rental RV for the period that you will be driving it. You will want to make sure that you have proper and adequate coverage for everything that could possibly happen on your trip, such as collision, liability, fire and theft. Make sure that the coverage includes acts of nature.
Pay for your RV rental with a credit card that you know carries additional insurance for vehicles that you rent. It would be a good idea to call the customer service department to discuss your actual situation prior to using the credit card to rent the RV.
Ask the RV rental company about insurance companies that they recommend for RV insurance coverage. Check these out before you agree to pay any premiums. Know what the deductible would be and how the claim process would work. Also, check all your rental agreement documents to see if you are paying for RV insurance within your rental agreement. If so, obtain what it covers in writing, as you may still want to consider additional insurance on your own for added security and insurance protection.
Talk to members of RV travel clubs for suggestions on insuring RVs. There should be many suggestions of insurance companies to use to insure your rented RV.