So on one of our days on our upcoming September trip my wife and I will probably be starting in Erfurt, visiting Wittenberg and finishing up in Berlin. Probably staying several hours in Wittenberg. I'm thinking the best ticket strategy would be to buy an Erfurt to Wittenberg IC ticket for each of us, and then purchasing the Berlin Brandenburg ticket that day in Wittenberg when we are ready to head to Berlin. Am I missing something or is this the best option, as it gives us lots of flexibility on when we want to leave Wittenberg, plus is cheaper than an IC ticket Wittenberg Berlin, and the trip is only 40 minutes slower.
You could book a saver fare ticket Erfurt - BERLIN (use caps to make your ticket valid to any S-Bahn station in the inner zone) and request an defined "intermediate stop" in Wittenberg (www.bahn.com / further options / add intermediate stop / via ... ). Vey often a ticket like that is not more expensive than the direct ticket.
E.g., for the departures at 8:28 and 9:28 on a weekday in mid-September the price is €25.90, regardless of whether you have an five hours overlay in Wittenberg or not.
It is less expensive to buy Supersparpreis tickets now Erfurt to Berlin with a fixed stopover time in Wittenberg with both connections are ICE trains. 39.80 EUR for 2 people and you must take both trains. If you want more flexibility for the the continuation to Berlin, then the Erfurt-Wittenberg is an ICE that you must take, but the Wittenberg-Berlin is a regional train. That is 51.80 EUR for 2 people. Then you can take any regional to Berlin from Wittenberg.
I have heard that finding luggage storage in Wittenberg can be challenging. Very few lockers at Wittenberg Hbf. Maybe someone who has been there recently can comment.
Thanks for suggestions sla and sam. Didn't know about the intermediate stop function. Also, Wittenberg TI said we could leave luggage in their office, if no lockers are available at the train station.
Please note that there are two tourist informations in Wittenberg, one opposite the Schlosskirche, the other one in the Stadthaus Mauerstraße 18 (at the northern edge of the inner town, a little closer to the railway station, and, different from the other one, in a big new building with a lot of space).