Monte Carlo should be a fun place to explore on foot. There are steep hills everywhere but there are also escalators and elevators here and there to ease the climb. This map is kind of awkward and hard to use but it shows a lot of detail including said stairs & elevators. There are also lots of busses and taxis to take us where we want to go.
We still need to do some research on Monte Carlo to find out where else we want to go but I'm sure we will want to see The Prince's Palace the apartments of Albert II, Prince of Monaco (Albert Alexandre Louis Pierre Grimaldi.) and of course the Monte Carlo Casino. I have been reading on the Cruise Critic board that you don't really need a coat & tie to go inside the casino. Pants and a polo shirt are reported to be OK.
From what I have read, Monte Carlo is a very expensive place frequented by very wealthy people. Kind of like a combination of Beverly Hills and San Clemente on steroids? We may feel a little out of our depth here.
We are supposed to dock in Monte Carlo at 10 am. If we rent a van as soon as we get off the ship we can see St Paul, have lunch near there and then have the afternoon to explore around Monte Carlo and the casino.