Ideas for visitor - Baden-Württemberg

A relative of mine will be visiting me next spring, and I am out of ideas what to do with her while she's here. I thought I'd ask you folks! She's perfectly healthy, but 76 and an American. She prefers not to walk long distances (10 minutes is about the limit), and stairs and inclines - not to mention hills - cause her to grumble. On her last visit we took her to Hohen Neuffen, and when we reached the stone wall at the entrance she sat down and said she'd wait for us. She fears the sun (her father had skin cancer), so being outside isn't really her thing. She says she “has no sense of smell or taste”, so going to nice restaurants is a waste.

I do my day trips by bus and rail, which means a good deal of walking. When I asked her what she would like to do in light of all the things she doesn't, she said “just visiting” (chatting & small talk) is fine with her. We're probably talking about a week's visit.

Any ideas besides encouraging her not to come? I'm looking for possibilities that don't involve: walking, being outside on a sunny day, stairs, hills, or inclines, or Hohen-anything. She has been to the area several times, and each time her issues with getting around have gotten worse. She is not overweight; she just doesn't like to walk or be outside, even at home.

This is part of expat life as well – hosting guests who may be better off staying home. ;-)

You said Baden-Wuerttemberg, but given that you mention Neuffen, which is one of the nearest visitable castles from Stuttgart, I assume that you are not too far from that city.
If so, there are plenty of easily reached museums (Mercedes and Porsche being the most famous), a historic cable car, a park steam railway and the chapel with great view on Wuerttemberg (easily reached by bus, followed by only a short walk uphill).
You should also visit a Besenwirtschaft (informal winegrower's inn) with her, if not for the local food then for the local culture.

The Killesbergbahn - thank you! Excellent possibility, which I did not know about. She's been to the Mercedes Museum, and although she has zero interest in cars (same with me), the history side of it is very interesting and she liked it as well. I'll look into the Porsche museum. I know the walk up to the Rotenberg Chapel (I walked there from Esslingen - a lovely experience!), and she would opt out if she saw the hill beforehand, and might refuse upon arrival. It's worth a try, though! And I've been wanting to go to a Besenwirtschaft myself - another nice idea.

Thanks, Beppi! This has already helped.

The Porsche museum is not about the history of the car and the social changes it brought (which are very well shown at Mercedes), but purely about the brand's muscle cars.
You can take bus 61 from Untertuerkheim to Rotenberg - from there it's only 300m (but uphill) to the Wuerttemberg chapel. (And then it's a 1.2km downhill walk to Uhlbach, which has two nice Besenwirtschaften and the best wine in the region.)
On the way from Esslingen to the chapel, you probably passed in front of our house (Obertuerkheim).