Has any one stayed in this hotel that can give us a recommendation good or bad?
Never stayed in Kelsterbach, but I have stayed in Mainz. There are three hotels, Hammer, Königshof, and Schottenhof just across the Bahnhofplatz from the station. From there it is a short S-bahn ride to the airport. Of the three, I have only stayed in Schottenhof, but I like the looks of Königshof (www.hotel-koenigshof-mainz.de) and will stay there next time.