Having grown up in Dayton, OH I can completely agree that Dayton is a wasteland. There isn't much you can find in Dayton that you can't find in Columbus so save yourself the hour long drive, and don't go! (The Air Force Museum is kindof interesting though if you like museums.)

The Polaris Shopping Center is an upscale mall, nice for the area, but nothing spectacular if you have been to other upscale malls. However, the Easton Mall is quite an interesting place. The owner developed the property himself and even paid to have the highway exit installed. A great place to grab a meal, people watch and go out for an evening. (There's an Irish Pub right next to the Barnes and Noble that gets rowdy during European Football games.)

As for the whole priceline experience...pick a 3 or 4 star hotel. Don't go walking about if you are unfamiliar with the area; like any city Columbus has its bad parts. But, on a mileage run, the idea is to maximize the mileage per dollar right?