Villefranche (Nice) and Santorini required tenders (I am obviously unsure about Mykonos)...
I know there is a train from Villefranche to Monte Carlo as a couple of our tablemates took it...
There may also be trains available Livorno to Florence...The train system in Europe is much more comprehensive than here in the US...Try searching the net for schedules...You want to make sure you get back to the ship in plenty of time...
It took us about 45 minutes to get from Civitavecchia to Rome (the shore excursion brochures say 1.5 hours....it may be that our minibus took restricted highways or just good luck with traffic)...
Florence is a good ways inland, probably well over an hour...
The ship also offers "on your own" excursions which are basically just bus rides to and fro...but they don't want to undercut their excursions by much so they tend to be pricey for what you get...For Florence, for example, it's $79 per person...You get about 6 hours on your own in Florence...Their next level up is the "Taste of..." excursions...$92 getsw you a 3 hour guided tour and 3 hours on your own...
The Nice version of the "on your own" gives you 2 hours in Nice and 3 in Monaco for $60...
They basically drive you directly from the ship (or tender dock) to a point in town and drop you off with an appointed meeting time for the return...
I would guess the cost of a train or bus ticket in each case is considerably less...the trade off is you need to get from the ship to the train station and back (not always walking distance) and you need to be very careful about the timing of your return...
