I agree about the land tour before the cruise. The land tour often involves a lot of packing and unpacking of the few things you should take on the land tour, and getting up early to take the next bus, train or plane. On the cruise, you're still doing a lot of sightseeing at each port stop, but you've unpacked just once, your meals and entertainment are included, and it's a more relaxing experience.
Be prepared to NOT take all your luggage on the land tour. Often your main luggage is sent ahead to pier storage because the buses/trains you take on the land tour can't store big suitcases.