Wendy,
Your analysis of a cruise vs. a land tour makes sense. Up until this year, we have always done land tours concentrating on one area of a country at a time. But cruising gives us opportunities to see cities or islands we probably would not get to via a land trip. We will also get a good taste of new places that we can always return to later.
And cruising on RSSC makes these cruise trips all the more wonderful! Like you said, combining a cruise with a land tour is a great way to go if you have the time.
Ginny