I just arrived in Bad Nieuweschans. The most northern Dutch-German border town with a railroad connection. It's connected to Groningen with a very regular Arriva service.
Tomorrow morning I'll first take the #RailroadBridgeReplacementBicycle to Leer (as since 2015 the Friesenbrücke is temporary out of service... ) and then trains via Bremen and Hamburg to go home.