Severe arthritis - advice for princess shore excursions?

My mother has severe arthritis and difficulty walking and getting up steps. We always use to go on the Princess shore excursions but she gets embarrassed since she is so slow and often will just stay on the bus if the stay is short since she does not like getting on and off.

What do others do in similiar situations? She always says she never sees anyone like herself on the tours so what do people do -just book a taxi cab tour?

We are looking to go to australia and new zealand, the 16 day southeast Asia cruise or holy land (eventually all three but one at a time now!). Any advice on which is best?

She would have no problem getting on a bus and walking for a minute or two to each site. We have also thought of getting her a wheelchair but am not sure what they do w the wheelchair on the tours since most do not say wheelchair accessible,

Of the three cruises you are looking at I have only done the Holy Land. I use a travelscoot scooter and either a rollator or two canes for short distances (like in the cabin from the bed to the bath). I am much happier when I can arrange independent tours such as the one we took from Alexandria to Cairo with Nile Blue Tours. I am quite tall and can transfer easily into a van which was used for this tour. I have most trouble with large buses but can manage with assistance from my husband. I sometimes use the tours marked as "easy" by Princess. These tours can usually take a foldable wc or scooter but are not truely accessible as you have to climb the steep steps to the bus. The most disappointed I have ever been on a tour was an "easy" tour to Jerusalem. We spent two hours at a "tank farm/museum" while the able bodied tour buses went to the Jerusalem. When we arrived we had to park almost a mile from The Church of All Nations. Needless to say those of us who were handicapped did not get off the bus while our companions walked there. We also had a guide who lacked skills in time and people management. I wish I had made private arrangements there as well. The next day I took a standard (non easy) ship's tour in Galilee. It was excellent with an outstanding guide. I did choose to stay on the ship at two of the venues but had a wonderful visit to a kibbutz and the Jordan River.