Thanks. I would probably have to keep these a couple weeks before we decide for sure. (Waiting and hoping for the cruiselines to offer some great last-minute savings. )

Would it be an option to keep just the one I have, then switch the last leg if we change to the other city? (We already have a connection within Europe for the last leg.) Or would changing the final destination entail an entirely new booking and if there is no space on my current US-EU flight then, I'd be out of luck?