Dom Zum Heiligen Kreuz is just one of the places to see in Nordhausen, so why not enjoy the other things to explore during your travels? While you're in the area, wander around the forests.
You can get tickets for a performance at Theater Nordhausen/Loh-Orchester Sondershausen on your trip to Nordhausen. Take in the museums while you're in the area.
You can spend time studying the exhibits at DDR-Museum during your travels in Klettenberg. Amble around the area's forest or experience its musical theater.