I need some guidance in setting up train itinerary for Germany/Belgium/Fran

I am trying to decide how many days for a rail pass I should get. I am thinking of getting a bahn pass for Germany and for the trip to Aachen from the Brussels airport and from Germany to Rheims, France and a separate pass for France and Belgium. Here is my itinerary: Day 1: Landing in Brussels: Aachen & Cologne Day 2: Trier Day 3: Mainz Day 4: Nuremburg Day 5: Nuremburg, Rothenburg ob der Tauber, back to Nuremburg for the night Day 6: Salzburg, then to Augsburg for the night Day 7: Munich Day 8: Munich Day 9: Augsburg to Fussen then Overnight train to Triberg im Schwartzwald either from Fussen or Augsburg. Day 10 Triberg, Alpirsbach (staying in Triberg) Konus Day 11 Freidburg or Basel (staying in Triberg) Konus Day 12 Basel or Freidburg (staying in Triberg) Konus Day 13 Black Forest or Stuttgart: Overnight train to Rheims, France Day 14 Rhemis Cathedral, France to Chartres Cathedral to Paris Day 15 Paris, France Day 16 Paris, France Day 17 Rouen, France Day 18 to Ghent, Belgium, to Brussels, Belgium to the Brussels Airport at night. Thank you .