Brithish Isles cruise or land tour?

We need some advice from UK experts. My DH and I booked a British Isles cruise on the Royal Princess for next May. Now we're having second thoughts and wonder if a land tour would be better. Neither of us have been to the UK before. We are experienced cruiser but have never done a multi day bus type tour. We would appreciate your suggestions.

We have done the round Britain a few times and we live here.

For a first snapshot the cruise is good as to do Scotland and Ireland on a landtrip is a lot of travel.

Be very focused on what you want to do in each port.

London/south can be done as an extension at the beginning.

Jump ship early and return via Paris.

(don't fall for the day trip bus ride).