Trains and passes

There is no way from Mainz to Boppard by ship in the afternoon, but if you can get to Bingen Stadt station, there will be a boat at Bingen at 4:30 pm if you can make the S-bahn to Mainz by 2:59 pm with a connecting regional express. Cost if you buy an RMV Gruppentageskarte covering 4 adults (16 yo is an adult) for 28.30 EUR.

You can use a Quer durchs Land Ticket to get from Boppard to Rothenburg using all regional trains for 68 EU.

Rothenburg to Nuemberg is a VGN Tagesticket Plus for 19.10 EUR.

Nuremberg to Berlin, you can get a Sparpreis ticket (nonrefundable except with fee) on a direct ICE in 5 hours for 319.60 EUR.

Round trip to Wittenberg with a Brandenburg-Berlin Ticket for 29 EUR.

Berlin to Frankfurt with a Sparpreis 1st class (nonrefundable except with fee) on a direct ICE in 5 hours for 139.60 EUR.

That comes to 599.10 EUR for the 4 of you.
Edit- For a bit more flexibility, get 2 German 2nd Cl 3-day Flex Twin passes to cover the 3 big travel days for 586 EUR, then the 3 cheap trips added comes to 655.90 EUR.

Sam,

Thanks so much. Let me paraphrase in my own words for the tradeoffs.

The lower price p-p tickets usually come at the cost of either longer rides, more transfers, or less desirable hours. If we pick our ideal schedule, the p-p cost is higher and makes it easier to justify the German Rail Pass -flex option.

The only other one I saw that might help was the summer ticket for under 27 for the 2 kiddos. (4 trips @ 24 for one and 4 trips @ 19 for the younger one)

If we have a German Railpass - can that be used for the KD boat too?

All of this is moot if we cannot but the passes at the Frankfurt airport....

The only other one I saw that might help was the summer ticket for under 27 for the 2 kiddos. (4 trips @ 24 for one and 4 trips @ 19 for the younger one)

I have not seen this. Can you cite a website?

The GRP flyer states you get a 20% discount on the K-D boat. I am assuming that is on a rail-pass day. Its nothing to write home about.

It seems that you can buy passes at DB Reisezentrums, of which there is one at Frankfurt Airport.

Taking that Köln-Düsseldorf boat up the Rhine used to be free when you presented your Pass. Now, you get more of a discount on a ferry to Finland from Germany with a Pass than on the K-D boat.

All right, I've had time to sleep on this one.

I don't see a German 2nd cl Youth Twin Flex Pass, only individual passes. A 3-day is 157 EUR, so for 2 that would be 314 EUR. This is still more than the cost of an Adult German 2nd cl 3-day Twin Flex Pass for 292 EUR. So that is the way to go.

You have 6 travel days total. I've already gone over the cost of combination local verkehrsverbund tickets (8/15,8/19, Berlin-Wittenberg), QdL ticket (8/18), and Sparpreis tickets, (8/20,8/27). 599.10 EUR with restrictions as to time of travel, advance purchase train specific,

Alternative to get 2 German 2nd cl 3-day Twin Flex Passes for 584 EUR (2 times 292) plus the local tickets on the other 3 days for 71.90 EUR bringing the total to 655.90 EUR.

The 4-day, and 5-day passes seem to be in a sweet spot, at 314 EUR and 335 EUR. So if you got 5-day passes, the cost would be 670 EUR plus 19.10 EUR for the trip on 8/19 bringing the total to 689.10 EUR. This would bring in several advantages.

On the day of your arrival, you would be using a pass day, so you would get the 20% KD discount. Secondly, if your flight was delayed, or you had a big delay getting through immigration (it happens, job actions, whatever) and you could not make the 16:30 KD boat at Bingen, you could still continue on to Boppard that day on the train and be covered.

On the day trip to Wittenberg, you could take an earlier fast train and not be restricted to traveling after 9 am or only local trains to and from.

The trip from Rothenburg to Nuremberg will always be best with the VGN Tagesticket Plus. There is no advantage as to time (its a Saturday), number of connections, or travel time. There is a connection every hour to Nuremberg and it takes from 1 1/4 to 1 1/2 hours to get there. That is a local verkehrsverbund ticket, the Greater Nuremberg Transit Authority (VGN). 19.10 EUR covers all of you for the day and includes local transit (buses, trams, U-bahns) in Nuremberg.

For the long distance trips, especially Nuremberg to Berlin, you might also want to spring for seat reservations at 4.50 EUR each to guarantee you can all sit together. It is a Sunday and appears to be busy because the Sparpreis tickets are already expensive or nonexistent on certain trains. Among other things, the Bayreuth Festival is going on at that time.

Hopes this helps.

Sam,
I cannot tell you how much your help is worth to me. (A lot!) Here is a link to the youth passes I mentioned:

https://www.bahn.com/en/view/offers/germany/sommerticket.shtml?dbkanal_007=L04_S02_D002_KIN0060_NAVIGATION-LINKS-SOMMERTICKET_LZ01

The timing for Rothenburg is accidental to happen during their wine festival. Nurenburg is just a convenient launch point to Berlin. I really wanted to go to Bamberg but it looked like a bit too much juggling.

That looks like a great deal!
One thing is that it must have an IC, EC, or ICE train in the route. That is not a problem for the 8/18, 8/20, or 8/27 days, but presents a little problem for the the other days.

There are none of these trains useful to get you to Bingen Stadt on your arrival day in time to make the KD boat at 16:30. That boat, by the way, is the classic paddle-wheel steamer.

Using it on 8/19 would limit you as to choice of departure times as there are only a handful of IC trains you can use during the day.

That leaves the day trip to Wittenberg Lutherstadt. There are a couple of morning trains, one and IC and the other an ICE. You could use those. Since the Sommer Tickets are only good for one-way journeys, they would just have to buy Flexpreis tickets for the return, or Berlin-Brandenburg tickets if on a regional train. Worst case, it is 64 EUR for 2 ICE tickets.

It looks like they have to be purchased by Aug 15 with the travel dates picked, but they are not train specific.

So that would give you 606.80 EUR total ticket costs. Your Twin Pass at 335 EUR, VGN Tagesticket Plus at 19.10 EUR, 8.35 EUR times 2 for the kids from Frankfurt to Bingen Stadt (oldsters are traveling with your pass), 18-26 4-trip Sommer Ticket at 96 EUR, Under 18 4-trip Sommer Ticket at 79 EUR, 32 EUR for ICE Flex tickets W'berg-Berlin for the kids. Also, looks like you would lose the 20% discount for the KD boat for the kids. There may be a youth discount for that, but I don't know.