DES MOINES, Iowa — I used to say the best way to see a city was to stay downtown and go for a run. You get in a workout, and you are able to see what a city has to offer (always tell the concierge your route). I don’t run as much as I used to, but on a stay in Des Moines recently I got caught up in a downtown 5K, which proved to be a perfect introduction to the Iowa state capital. I began my fall morning setting out from the downtown Marriott, hoping to see the famed Pappajohn Sculpture Park. It was only about a half-mile away, so I decided to walk to it. The free 4.4-acre park sits at what ma…