I assume this is for two people.
If you purchase train-specific non-refundable tickets ahead, online, Berlin to Dresden and Dresden to Rothenburg can be €29 each leg per person with Dauer-Spezial tickets. Freilassing to Interlaken and Interlaken to Bacharach can each be €39 pP with Europa-Special Schweiz tickets. Salzburg to Freilassing, point-point, is €2,10 pP.
Rothenburg to Munich and Munich to Salzburg are €28 for both people with Bayern-Tickets, €14 pP, purchasable the day of travel.
That's €166,10 pP (~$236) for the whole trip vs. $481 pP with a 6 day saver pass. You could save almost $500 by skipping the railpass. Of course, the railpass is for 1st class vs. 2nd class for the German Rail promotional and Länder tickets.