Hi, all, I'm looking for tips for traveling/sightseeing in Europe for people who are older and/or not in such great health. My parents, who are in their 70's, have come to visit me in the Freiburg area, and it's becoming clear that their health/general energy level has declined a lot since their visit last year. Previously, we would meet up around lunch, and walk/drive around visiting sights until dinnertime, eat together, and then go our separate ways.
This trip, we did an afternoon walking tour of Freiburg one day, and they seemed a little haggard at the end of it, so we went to the Black Forest the next day just for lunch at a lake resort, and they were super tired after that, so the next day I just took them to some very small local sights, a crumbling hill castle with a nice view a ten minute drive from their hotel and a nature preserve a ten minute drive from there. We had lunch in a tiny town a fifteen minute drive away, dinner at my house. Today, after that, they're so exhausted they're taking a nap after breakfast.
I really don't know what to try that would be lower-key. I'd previously brought up the idea of taking them to visit the Therma (the cool one with so much CO2 you get bubbles on yourself!) and they shot that down. They don't like wine and they're not really interested in sampling the local cuisine because they're too full from breakfast and German food is too sugar and meat heavy. Maybe a scenic train? My backup plan really was to take them to a series of small castles and scenic nature spots within a 20 minute drive but it seems like this really is too much. What would you recommend?