Mosel Valley need help!

You might stay somewhere on this pleasant portion of the Mosel, which is great not only for the bike route (red) but also for the day cruises you can take between Traben-Trarbach and Bernkastel (a stunningly attractive old-world town.) T-T has train service on the "Moselweinbahn" railway from the rail junction town of Bullay (which is only 10 train minutes from Cochem on the main Koblenz > Trier railway, the "Moseltalbahn.") Cochem is not shown on the map but lies in the direction of Koblenz from Bullay. See this map of the two railways.

River cruise schedule for Traben-Trarbach > Bernkastel - timetable is bottom-left on this page. You can take bikes on board for a small charge if room allows.

Bikes are also permitted on the trains. Bike rules for the Moselweinbahn and Moseltalbahn Railways mentioned:

https://www.vrminfo.de/en/tickets/tickets/cycle-ticket/

For the Bullay > Trier route, a bike ticket is required before 9 am on weekdays. None is needed otherwise.

https://vrt-info.de/tickets/fahrradtickets

There is also a network of buses specifically for bike transport. Lines 220, 330 and 330 might be most relevant for the Bernkastel - Traben-Trarbach - Bullay river segment.

https://radbusse.de/pages/radbusse-ueberbklick-engl.php

https://radbusse.de/pages/start-eng.php

Our most recent stay was in the small town of Kröv... https://www.kroev.de/ Quiet place with nice scenery and a small handful of services. Bullay has also been a good base town for us, similarly quiet and lovely. T-T and Bernkastel are bigger with more of the things tourists are often looking for. Bernkastel gets very busy during the day with tourists.

Bike rental facilities on the Mosel:
https://en.visitmosel.de/cycling/service-information-tips/bike-hire-points

How awful for you on such short notice! If you still want to bike, but cover more area, BikePlanet has a an 8 day tour starting the 15th from Heidelberg to Cochem which goes along the Neckar, the Rhine and the Mosel and appears to have availability. I am sure other folks on the forum will have recommendations. I am not aware of wine tours, but Bernkastel-Kues would be a good base. I can recommend the Hotel Weisskopf which is across the river and on a slight hill with great views at a reasonable price. Good luck.

I think your problem is going to be availability, and in some cases, minimum stays - especially on weekends. You may even have to stay on the Rhine. I noticed that Traben-Trarbach was a real "bicycle town". Maybe you can get a B&B on a wine property, maybe more rustic than you want. I noticed at least one in T-T, which was an attractive place. B-K struck me as over-touristed, but it did seem to have more hotels than other towns. You would feel free to spend less time in B-K if you had seen Fachwerk close-up in other places already. I wonder if Trier has hotels?

We stayed at a luxury-level resort in Mulheim, Weinromantik Hotel Richtershof, Hauptstrasse 81-83, D-54486, Mulheim weinromantikhotel.com . Very small, and this would be a big budget increase. You should also note that "name" wineries on the Mosel are likely to require advance reservations for formal tastings, often with a prepaid fee. This will also be tough at the last minute. Will the cancelled company "give" you the tasting booking that they had on hold?

Trier is a much larger town, but would be an excellent place to base yourself if there are no available rooms in the smaller towns on the river.

There are a number of boats docked in Cochem, most do a circular route, going up and down river, stopping a few places, but most use them for sightseeing. The trains are handy and frequent, and accommodate bicycles. You will have lots of daytrippers, people doing weekends, and campers, basically doing the same thing you wish to do.

Weekday rooms in the Mosel towns might not be too hard to find. The place we stayed in Kröv - Der Weinladen - is available for June 18-21 at less than €90/night double with a balcony, a view of the river, and breakfast on booking.com. We boarded the cruise boat to Bernkastel right there in Kröv.

Thanks everyone for the great suggestions. We have made reservations in two towns and are on our way! Happy travels:)