Just limit yourself to NRW=the big NordRhein Westfalen Land. Koblenz is some 40-50 KMs out of it. The best known more scenic views over river Rhein are more further south-Lorelei etc.
This 49/DE-ticket (I now have a subscription since 1/6, but I am dutch and have family there, so visits are far more often) but from notes on other touristy forums I gather that ordering this online via HVV-switch allows payment with cred.cd and it can start immediately for the rest of that month on an adjusted pro-rate price-but you are forced to take then a whole month after that and need at actively cancel it before the 10th of that month to stop. So if you f.e. need 6 days end of sept. total cost would be 1/5 of 49€ for sept and 49 for oct-that is all p.p. But for using it 7 days that would make it still less as 10€/day, a great bargain. This is the only one to actively order before-all others mentioned an just be bought-on the day or before from counters or machine.
This VRR and NRW-Landesticket is valid in ALL local transpo-also metro/tram/(trolley)bus, but mo-fr only from 9.00. (that is still 8.00 am in GB).
This VRR-RHein Ruhr Verbund area has some 7 tramway systems, 1 Schwebebahn in Wuppertal and the extensive trolley system in Solingen included.
It also allows short visits into NL=Nederland: Arnhem and Venlo are allowed. For trains ; DO, repeat DO expect delays-and cancellations, but also the chance to hop on a train that should have left 20 mins before when you enter a station. And by far it will not be just DB: a name most familiair to you-Nat. Express, can also be seen on a lot of trains over there. Running train comp. is not announced or referred to.
And if you feel very British and cannot start proper with out that Brekkie: Premier Hotels are now also in Germany and have HTLs in f.e. Essen (a high rise next to the station with great views over it) and Düsseldorf, but not Dortmund (yet?). I have found them good value and standard.
The airport in DO only has buslinks and the usual bus to station is independent and out of all these ticket offers. To use it from there its a local normal bus to next metro/light rail stop and use that (change again for station).
www.vrr.de
fahrkarten.bahn.de
www.bahn.com
