I echo Jenny: All of the information has been helpful. There are many discount options, each with specific restrictions. I noticed that some require at least one person has a Bahn card and others can't be used in conjunction with Bahn cards. And the regions are confusing. Here's my basic itinerary, and this is for two people.
Arrive Frankfurt and immediately take the train to Nurnberg. Looking at the difference between Sparpreis Aktion and regular price, we'll commit to a specific train and hope there are no significant delays. Expected landing is 07:30 so we'll plan to be on either a 9:35 or 10:02 train. Any thoughts?
We then spend nine nights in Nurnberg. In addition to exploring that city, we plan a number of day trips. We'd prefer not to schedule all of these ahead of time so we have more flexibility. The best transportation I could find for Coburg is a Regio Ticket Franken Thüringen for 26 Euros. For regional tickets, do we buy ahead or on the day of travel?
For Bamburg we came up with a Tages Ticket + for 19.10 Euros from VGN. We could use the same ticket for Rothenburg ob der Tauber if we visit both on the same weekend? I noticed a previous writer suggested buying this at Konigstorpassage instead of Bahnhofsplatz in Nurnberg, but the latter is closer to where we'll be staying. Do the folks in the station really not know the VGN tickets? Again, can we buy these a day ahead or on the day of travel?
For a day in Wurtzburg I found a Bayern-Bohmen Ticket for 34.60 Euros.
The best price I came up with for Regensburg was 52 Euros with a Quer-Durch-Land Ticket.
When we leave Nurnberg we're heading to Mittenwald for a change of pace. I found a Bayern-Bohmen ticket for 34.60.
From Mittenwald to Augsburg there's a Sparpreis for 38 Euros, and from Augsburg back to Frankfurt there's another 38 Euro Spar Preis Aktion ticket.
Am I correct that I can buy the Sparpreis tickets through the internet and just print them at home? If I'm making any glaring mistakes in my planning, please advise!! And again, thank you to all who are willing to take their time to share their experience.