I took 3 part time jobs after I retired.Well I'd definitely agree that driving and seeing new roads and scenery is better than sitting around the house.
But I thought maybe you had family to see or some kind of hobby that required travel.
As far as the health benefits of driving, I don't see sitting in a vehicles for hours at a time much different than sitting on the couch. You exampled mileage was extreme for a single year at the wheel. If you want health benefits you shoulda' walked that far.