50 feet round trip per stop? You are being too conservative on your distance estimates. I know routes vary a lot, but I doubt many of us deliver to houses sitting 25 feet from the street. I have two small subdivisions like that, its easy to knock out 25 stops per hour.
Using your route and distances, you would only walk 7,500 feet a day, or about 1.3 miles. I have a pace of about five feet, meaning that is how far two of my steps are on level ground, so this is about 1500 paces or 3000 steps all day.
My route usually has about 140 stops, but I probably average at least 100 feet at a stop. So my numbers would be twice of yours. 14,000 feet or 2.6 miles. My route would have 2800 paces a day, or 5600 steps. I am sure somebody from IE has some kind of national average.