"Oh dear you are struggling - I walked up Hay Bluff the other day!"
"Really? Pity you didn't stay up there then."
Some people are just tone deaf, and to be pitied for it really.
Well done for going with the family. Unfortunately these ancient houses are very rarely accessible 😕
My mother-in-law's mobility declined but she still enjoyed coming on holiday with us.
One year we went to Mount Teide on Tenerife, my husband and I wanted to go up in the cable car but she said she'd stay in the café. We settled her with a coffee and when we returned, another customer had seen her on her own and bought her a second coffee!
I'd suggest you keep accepting invitations, but adapt to your own limitations.