Last summer I started a Honda that had been sitting in a garage for 10 years without running. All I did was replace the battery, oil/filter, drain and refill gas, and pull the plugs to spray some wd40 in the cylinders. Tires were not a noticeable issue at all, still originals from 1987 with no signs of flat spots or dry rot. Maybe being a light car it wasn't as bad? But I know the tires were flat for an extended period of time a few years ago. No problems now though.