I get a flight physical that PHYSICALLY determines if I am still safe to fly my own plane. There is also a flight test that goes along with my physicals to determine if my flight skills have deteriorated.
Perhaps you should talk with your family doctor about annual physicals specifically geared towards your vision, reflexes, and cognitive ability, as they pertain to driving. This might even include a road test to see how well you handle the RV.
Sometimes an outside source is the best way to get an honest opinion of how you are behind the wheel.