I'd certainly not leave her at the hotel for the morning. Even if she got to a section that she thought was dificult, I still reckon she'd enjoy being there even if she sat down at the bottom of the walk , near thwe ticket ofrfice and just enjoyed the woods and the birdsongs.
Actually, most of the walk isn't strenuous at all. It's on a sloping path built with stone blocks and not too steep.
The only part she may have dificulty is the section near the bottom where the path has collapsed. It was once built of huge granite blocks which can be seen laying around but now the walk through that bit can be uneven but I don't class it as being too dificult. You'll probably find that she'd cope well, maybe needing a hand on just one or two places that require a big step upward.
If it was me someone was considering leaving back at base, I'd be jumping. I'd at least want the chance to have a go and settle for sitting down and enjoying the woodlands if I found it too dificult but I reckon she'd cope.