Thank you all for the great suggestions! The current game plan is that she will be coming. Our schedule was to fly direct to AMS, tour Amsterdam for a few days prior to the cruise, then take a small KLM plane to Basel to get on the boat. As we booked all our air with Viking nothing is able to be changed at this point so that's what we're going with. She can get around on crutches but only for short periods, however, we plan on bringing a foldable wheelchair so we can get a bit further from the hotel in AMS for sightseeing and off the boat when possible.
For anyone that's been on this itinerary, what ports is the ship directly at town center (or no more than 5-10 min walk so she can crutch off the boat and then get in the wheelchair and be at shopping/main area? I did google and chart the Viking docking places but I'm unsure if that's accurate. I'm thinking Breisach - yes, Strasborg - stay on board, Speyer - at least get off and go for a walk but won't reach city center, Rudesheim - yes but not sure we can reach center, Koblenz - get off but walk locally only, Cologne - walk locally only / no center, Kinderdijk - off but walk locally only.
Also, am I correct to assume that the docks that are not within walking distance to city center a shuttle bus is provided to reach the main hub?
Last question - if the river boat is rafted to another, is it usually another Viking ship so entrances and exits line up or could it be a random ship so a gang-plank and hopping over stuff is necessary?
Thank you for your time and input!