The tour description says this tour has strenuous walking/Stairs. Could those who have taken the tour comment on whether it was the nature of the sights that you went to that determined this? How much flexibility was there for those who may need to limit the walking , stairs? For example, our tour guide in Russia was able to point out the elevator (old one) in several museums and where my dad could sit to join us if he wanted to cut out a few rooms in the Hermitage. Also, do the hotels for this tour have elevators ?