i have a cruise coming up with one port of call Koper. I'm looking at excursion to Postojna Cave and Predjama castle. However, from the tour descriptions it sounds like the walking involved is somewhat more intense or not the most suitable for those who are older. Is this accurate for both the caves and the castle? I am traveling with my mom who is 75. She can walk but something that turns more into a hike is likely not a good fit.
Is visiting Piran a better alternative? What about Ljubljana?