My family will be travelling to the Rhineland in the summer, and I am just beginning to get to grips with the idea of "Verkehrsverbünde", or transport associations. As far as I understand, these offer advantageous tickets over a fixed geographic area, including "Minigroup" tickets that would be excellent for my family (3 adults + 1 child).
On longer journeys, one can travel over the territory of multiple transport associations in a single journey, even without a change of train. In these situations, the cheapest options appears to be to be the purchase of multiple tickets, one for each association.
For example, on a trip from Koblenz to Cologne, one could buy a day ticket as far as Unkel (Minigruppenkarte, VRM association), and then another from there to Cologne (Tagesticket 5 Personen, VRS assocation).
Is it possible to purchase these tickets at stations outside of their respective territories? I am aware of possibilities for print-at home and mobile tickets etc, but this seems to be a bit of a pain (downloading apps, printing tickets, and so on...)