I just returned from my first river cruise and I am blown away.
First, let me dispel a couple of myths because I had some concerns about doing this.
I am a 52 y.o. widow and travel alone. So I was fearful I would be suck with a bunch of old farts in walkers. Out of 140 or so passengers there were more than a handful younger than me. Only a couple of people seemed to have some physical challenges. For those people, AMA has tours (included in the price) that are specifically designed for them. For example, most had three levels for walkers: Active, normal and gentle. I never felt slowed down.