Train advice on German itinerary return from Amsterdam to Black Forest

Don't do Koln from Mainz, that's not worthwhile. There are a lot of things to see and do closer.

It would really help to know what interests you. History (WWIII, WWI, medieval, Roman?), Paleontology, Geology, Art (modern, what era?), shopping, eats, wine, fests, scenic outdoors, hikes, etc. All of these, and more, exist within the areas you're visiting in abundance.

Best planning is with https://int.bahn.de/en in English.

In the rural areas there are lots of wine festivals at this time. No really big ones, but real festivities of the people living there. Maybe you think of some medical procedures which might be cheaper woithout insurance than with insurance in the USA, espacially in France.

We were also thinking of day trips to Cologne from Mainz and Freiburg from Gengenbach

Rather than a separate day trip to Cologne, why not buy a ticket from Mainz to Amsterdam and include a stopover in Cologne along the way. Luggage lockers are available at Cologne Hbf.

Well I know the more experienced German travelers will get back to you later, but the one thing that stands out for me is spending 4 nights in Mainz. (I see you got some great suggestions to your other post already!) You could see what there is to see in a day, as I did in May. Be sure to prioritize the Chagall stained glass windows, details in TR below. I'm not even a modern art fan, and I spent at least an hour there. (Follow my train station suggestion, it's closer to another station than the central Mainz station.) And unless you've been to Amsterdam before, this is quite a short amount of time in a fascinating city! And a day trip to Cologne from Mainz seems out of the way, if you're going back to AMS anyway?

What about staying in Heidelberg instead of Mainz? It wasn't bombed in the WW2 and has a gorgeous old town, with a cogwheel train up to the castle. Here's my trip report, in case it's of interest. We really liked our hotel as well. https://community.ricksteves.com/travel-forum/trip-reports/6-nights-in-germany-mainz-heidelberg-heidelberg-was-gorgeous.

My girlfriend speaks zero German so I was able to see just how fluent everyone was in English. We had one server who didn't speak English the whole trip, so I wouldn't worry about it. And people were SO NICE!!

BTW. I would have 50 Euros in smaller bills handy. There were a few shops & one restaurant in the center of Mainz that didn't take cash. Hope you have a great trip!

Ticketing guidance:

Netherlands, Belgium, Luxembourg: RAILPASS:
https://www.eurail.com/en/eurail-passes/one-country-pass/benelux

(with enough travel days you can use it at the end to travel from the German border to A'dam as well.)

OR TICKETS:

A'dam > Bruges: https://www.seat61.com/trains-and-routes/amsterdam-to-bruges-by-train.htm

Bruges > Brussels: https://www.seat61.com/international-trains/trains-from-Brussels.htm#Brussels-Bruges (senior ticket)

Brussels > Luxembourg: https://www.seat61.com/international-trains/trains-from-Brussels.htm#Brussels-Luxembourg and...

https://www.b-europe.com/EN (senior fares available)

Within Germany: €58/each for the month of September, valid for unlimited use of regional trains and other local transportation: The DEUTSCHLAND TICKET

https://www.seat61.com/train-travel-in-germany.htm#Deutschlandticket

(Not sure about Luxembourg > Metz)

OTHER comments:

• I would add a night to Gengenbach

• I would cut Mainz and add a RHINE GORGE TOWN. Bacharach, St Goar, Rüdesheim, many options to the north of Mainz. If you wish to see something in Mainz, you can DAY TRIP there from any of these towns. The Rhine Gorge is dotted with fun old-world towns that are connected by train and by river boat.

• I would stay in Cologne at least one night; proceed from there to Amsterdam. Buy a saver fare ticket from DB (German Railways) to cover the whole trip to A'dam - or just to the Netherlands border, if you are using the Benelux rail pass through the Netherlands on this day.

https://int.bahn.de/en/

While I like the Rhine river valley, I'd much rather spend time in, and around, Mainz. The Roman ruins, the Chagall windows, the Dom, the Kirschgarden, the Gutenberg museum, the open markets, the really excellent places to eat...the list goes on. I visit Mainz much more often than any combination of the towns along the Rhine between there and Koblenz. And, if you do want to see those towns, it's just as easy to do that from Mainz either by train of boat. To me, that's the day trip.

And, as someone noted you'll be traveling during wine fest time. Not just the small ones either. the worlds largest winefest will be in Bad Durkheim in September. Personally I prefer the wine regions of the Pfalz to the Black Forest. There are a lot of old, walled, half timbered villages Americans never visit. (Europeans do, some, like Deidesheim, can be quite touristy in a lower key, more upscale, way; like Napa Valley.) Google places like Freinsheim, Weisenheim am Berg, or Annweiler.

https://reisenaround.com/bad-durkheim-wurstmarkt/

If what you want to see in Cologne is just the cathedral, then the idea of just a couple hour stopover is good. The cathedral is right by the main train station.

Sep 14 - 17: Base in Mainz - or in the Rhine Gorge?

Mainz, my one-year home many years ago, has some worthwhile things to see/do - the Dom, the Chagall windows in the Stephanskirche, the Gutenberg Museum, a few remains from ancient Rome... this page outlines the basics there for a day's visit pretty well: https://www.travelsavvygal.com/spend-one-day-mainz

KGC makes the case for Mainz. The choice probably depends a lot on your personal interests and your own preferences for the 4 days you have set aside for this area. Anyway, here's my case for booking within the Rhine Gorge.

1) Am I correct that your barge trip already includes the UNESCO World Heritage city of Trier (Roman sites, important churches, museums...)? Mainz is not unlike Trier in a lot of ways.

2) Is nature on your agenda during these 4 days? Mainz has a nicely-cultivated Stadtpark, but the Rhine Gorge provides oodles of extra-scenic walking/hiking/biking options - like the Rhine Castl trail:

https://www.komoot.com/collection/721/the-rhine-castle-trail-13-stages-of-pure-rhine-romanticism

3) Castles: Will you already have visited/toured a medieval castle or two during your barge tour? The best options for a visit are Marksburg (near Koblenz) and Burg Eltz (a Rick Steves favorite between Koblenz and Cochem.) Rheinfels ruins (south of Koblenz in St. Goar) is worthwhile too. Also interesting for you might be the Prussian-era Ehrenbreitstein (Koblenz.) Staying closer to Koblenz would makes these places accessible.

4) Scenery: Some Rhine towns (Boppard, St Goar, about 10 minutes from each other and 15 and 25 minutes from Koblenz, respectively) take full advantage of the dramatic river setting with lodging/dining options right by the river.

View from St Goar across the Rhine
Riverfont establishments in Boppard

5) "And, if you do want to see those towns, it's just as easy to do that from Mainz either by train of boat. To me, that's the day trip."

The Rhine cruise is a nice thing to do, but a day trip from Mainz by boat alone isn't possible unless you just want to sit on the boat for the entire day. 4 hours on the 9:15 northbound boat would get you to St Goar; before reaching the gorge, you'd have 2 hours of dull scenry to Bingen (the gateway to the river gorge) then 2 hours of the good part... Then after 13:15 your sightseeing on the ground could begin.. maybe there'd be time for the Rheinfels ruins plus a visit to Bacharach on your way back to Mainz - by train, that is; there is no boat back to Mainz unless you just stay on the boat that got you to St Goar as it makes the return trip to Mainz (18:40.)

Using the train to Bingen before a cruise - and/or skipping the cruise - would helpful if you want a slightly fuller day of sightseeing. But getting around from town to town, sight to sight or castle to castle... taking gondola and chairlifts to scenic outlooks... catching th ferry to the opposite riverbank, walking Oberwesel's old town walls or up through the vineyards to the Günderodehaus, or lingering in a Boppard wine garden... or at Gedeonseck... no day trip from Mainz can accommodate this type of visit.

All the Rhine towns have rail stations that are close in. But Boppard has multiple and solid choices for lodging/dining and a great location... AND a free guest card like the KONUS card:
https://www.vrminfo.de/en/tickets/tickets/leisure-tickets/vrm-guest-ticket/

Sept 11 Cochem toGengenbauh,
We will get Konus card from hotel , any day trips suggestions?

First, I agree with Russ that an extra night in Gengenbach would be good.

One excellent day trip would be to head to the Vogtsbauernhof (open-air museum) that is a joy to visit and easily accessible by train. This page from their website will give you specific instructions for taking the train: https://www.vogtsbauernhof.de/en/visit/how-to-get-here

Also, with your KONUS card, you can ride on the scenic Black Forest Railway line, which will take you through the scenic Black Forest and through some very charming small villages like Schiltach and Haslach. It can be used as sort of a hop-on/hop-off train ride experience. :-) You could combine that with a trip to the Vogtsbauernhof, although you might have to backtrack a bit.

Another good day trip would be to Strasbourg, France, which is a quick 40 minute train ride from Gengenbach (one change in Offenberg). The KONUS card will cover you until the border, and you just get a ticket for the short French portion (available at this site). Strasbourg is quite beautiful with a gorgeous cathedral, some wonderful museums and lots to see and do. I really enjoyed spending the day here. With regards to the French portion of the train ride, you would buy the Europass 24h mini pass, which covers the route to Strasbourg and back the same day for €7.80. You can buy it online, or from a ticket machine in Gengenbach or Offenburg when you change trains for Strasbourg.

Here is a link to info on the Europass 24h mini pass: https://www.cts-strasbourg.eu/en/online-store/fares/tickets. Scroll down to the very bottom (under the "Departement, regional and cross-border tickets" section) for more information.

Your Europass will get you to Strasbourg, and can also be used while you are in Strasbourg for local public transportation; like taking the tram from the train station to the city center. Return the same way you came, with both your Europass and KONUS card, in case you are asked to produce them.

Can you fly home from Frankfurt and avoid the trek back to Amsterdam? Note that while Bruges is easy enough to get to, it is a spur line trip, not on the main line to anywhere. Brussels (where you change for Bruges) is well train-linked to Aachen and Cologne.

Have you been to Amsterdam before? I understand Luxembourg for completeness, but there is a LOT to see in Germany besides Rick Steve’s’ favorites!

"Can you fly home from Frankfurt..."

Seems unlikely since you are leaving 10 days from now. Your impending departure date might also mean that you are totally locked into your stay in Mainz with non-refundable reservations. I don't know. But Boppard still has rooms on your dates in some nice places if you have left things flexible.

"any day trips suggestions?"

Mardee has provided good suggestions. I would add FREIBURG as an option, and further along the Black Forest Railway, Villingen, an attractive walled town, could be a good option too. Triberg, a Rick Steves pick on the same route, is possible as well.

BF Railway map: https://upload.wikimedia.org/wikipedia/commons/4/4d/Verlaufskarte_Schwarzwaldbahn_%28Baden%29.png

D-Ticket and regional trains: When searching for journeys within Germany at the DB site, click on "Deutschland-Ticket Connections Only" to bring up only those regional train journeys which you can take with the D-Ticket.

If you are pursuing any of the suggestions you have received, you would do well to act fast and/or get back to us with whatever questions you might have. Your clock is ticking. Your Germany > A'dam ticket at the end, if needed, will only get more expensive with every hour.

Thank you all for the overwhelming information, Our itinerary is pretty much fixed so your suggestions on day trips etc is most appreciated. I should have mentioned that our bike and barge is on the Mosel river with a group of friends which are all going in different directions so the last part of our trip is meant to take it a little easier. Art, architecture , local food and history are of interest. I'm sorry for not getting back to each of your excellent suggestions but we have been dealing with a strike at Air Canada.