I would highly recommend a river cruise on Viking. It is smaller and very flexible. We enjoyed getting to know passengers and crew. The meals were outstanding. The crew went out of their way to make you comfortable. Being able to unpack and not have to do it each day was a real blessing.
The lounge areas were most comfortable. Our tour director was the best I've ever had. I'm ready to do it again!
There was never a hitch in loading or unloading when transferring between the bus and ship. Viking had personnel available at each step of the way from the airport. It was the same with leaving. Getting the airport transfers was one of the best things we did.