In case you are scheduling a day excursion by rail to some city/metropolis served through the Rhein-Key-Verkehrsverbund (RMV) community which include Michelstadt or Mainz, You should buy each day ticket from the ticket vending machine at a Darmstadt tram halt, Which ticket will incorporate area tram/bus rides to/from your railway https://mitchn418bhm2.homewikia.com/user