There are going to be coach trips from the cruise ship into the cities, and Loch Ness. My wife worked on a few 10 day coach tours around the UK, and Ireland, it was all Turkish tourists, 2 nights in Glasgow and a coach trip around Edinburg then a few hours spare time in the city before going back to Glasgow. The North Sea & the Irish Sea can be quite rough if the weathers bad.
Aside from Loch Ness you are really only going to visit cities, so that limits photographic opportunities. Cruise ship use airport style scanners which you o though every time you board the ship.
Personally I'd fly over and hire a car, you very quickly get used to driving on the different side of the road. Early June before the school holidays accommodation is still reasonable prices, you can't go far wrong with Premiere Inns, and they are all over the UK and Ireland, but there are plenty of other choices, depending on your budget.
Ian