Same ship, same itinerary, same age group, love Chicago, but booked on the August 13th voyage - d'oh!
However if you want any info please feel free to ask. For your ports, we can advise that ...
Guernsey is a tender port which drops you right in the main town, which has plenty to see if you don't want to travel too far
Cork is actually a way off from your port of Cobh (ex-Queenstown). However apart from the ships tours, there is a regular train service from the dockside into Cork, also Cobh itself has plenty of interest (Titanic/Lusitania/Irish US settlers etc) if it's your first visit.
Dublin - it is unlikely you sill dock here, far more popular nowadays is Dublin Bay (aka Dun Laoghaire). This means it is a tender port, and whilst there is a train/tram service to Dublin, it requires a bit of planning, so check before you travel.
Liverpool should put you within easy walking distance of the city centre and all the main attractions so if you want to 'go it alone' there are plenty of options
Belfast will dock away from the city, and shuttle buses are the norm. However these (used to) drop you just across the road from the City Hall which give free tours, but you need to pop in there & sign up - they used to do 2 a day 10:00 & 14:00, so both are possible. We were also very surprised to realise that the unrest that haunted Northern ireland for so long is only a couple of streets away from the city centre. All the murals and the peace wall are still there so worth looking into if that interests you.
Glasgow is quite a train ride from Greenock where you dock, but certainly do-able. Having said that there is not that much to see/do in either Greenock or Glasgow, and last time we visited we went on a ship's tour which had scenic tour through the highlands to a picturesque vilage on Loch Lomond. Oh whilst I think of it, watch out for the giant on the dockside at the port as you arrive or sailaway - I won't say any more
Inverness is again possible to do by yourself, but not simple. You moor up in Invergordon, which lays (or laid) on lots of entertainment from locals and is quite a nice walk. But a tour may be the best option here. Again should be a good sailaway.
Edinburgh is nowhere near South Queensferry !! Some lines have dropped this tender port in favour of Leith from whch you can take public transport (or walk) into the city, but assuming that Princess don't then you can still catch a train into Edinburgh, and the station is in the centre of the city, the only problem is finding the railway station in South Q. (the station is Dalmeny) You have to follow the main road UNDER the bridge, then turn right following the station sign. There is (or was) a track leading from behind the pub where the tender drops you which provides/d a direct route, but again that was a couple of years back now, so may have been closed.
Paris/Normandy - the same story here, Le Havre is a nice town, but transfers to Paris or the landing beaches at Normandy aren't really an option, so if you want to do those ( and I would suggest you should ) then an organised tour may not only be the best option, but possible the most cost effective when you consider you would have to book a cab for the whole day as the driver won't be able to pick up any other business.
Right that was my whistle-stop tour or your ports, hopefully it's been usefeul, and will allow you to plan ahead & make the most of the trip.
As I said, if you do want any specifics, then please feel free to ask, and may I welcome you, and wish you a great time in our home country
Alan & Katrina