Agree re:small towns/overwhelmed. The trick, IMO, is to get off the beaten path quickly - i.e. don't go into the main downtown tourist-oriented strip. Instead, either plan ahead or simply walk where others aren't so you get a sense of the place. The thing to remember, too, is that if you want to do more when you're off-ship, those will be added charges - e.g. you can take a train up into the mountains, or a helicopter ride, etc... but it's definitely cheaper if you book outside of your cruise (though they will be more than happy to make reservations for you and take their cut!).
"In the absence of clarity, diversification is the only logical strategy" -= Larry Swedroe