I'd love any input on the Viking River cruise experience. On one side it looks quite relaxing and chilled out, on the other side I'm worried about too many group bus tours and being herded around, and also somewhat concerned on being the odd ones out in terms of demographics as we're in our late 20s.
Any feedback at all would be hugely appreciated.

Of course the demographics can change with the destinations and length of trip but I would say that those less than 30 will be in the minority. River boat trips in general do not attract too many of the young because the evenings after dinner are not too exciting. It's mostly early to bed and early to rise.

Viking is professionally well run and the trips from the boat are well put together and divided into acceptable small groups. Many areas can be visited on one's own.

I did a Russian river cruise with Viking in May and I am 58. I was one of the youngest on board, but it was no problem for me. You will be herded along on the shore excursions, but if you do your research before you leave and have a plan in mind, you can go off on your own as long as you are back in time to sail each day.

I have this question: what is the difference between an organized tour like Globus, Tauck, and a river cruise?

The more I read, the more it seems similar, only instead of a hotel you sleep on a boat.

Am I right? (thinking of going with Viking)

Which cruise? Makes a difference.

I don't know about Viking, but the Danube cruise I went on last December was nothing like a land tour. We were on the ship at night and sometimes during part of the day, but for the rest we were docked near intereting towns and could take a tour with a local guide or go off on our own, as we chose. I had a great time, and my usual mode of travel is in a car with my husband at the wheel.

This is exactly what I was afraid of: travel at night, go on a tour at daytime

But you don't HAVE to go on a tour! Most of the time I went off on my own, and that worked just fine. The main togetherness was at meals, and that was not a problem except the one time I was at a table with a women who had absolutely no conversation. I kept thinking "What would Jane Austen do?"