Ireland/UK Trip Help

You could easily spend 11 days in Ireland, and that's what I recommend. Add Derry and Belfast, as well as somewhere in the southwest like Dingle or Killarney. Cities aren't what Ireland is about.

For eleven days, I suggest just Edinburgh and London (4 and 7 days or 5 and 6 days). Are we talking about 11 full days (not including arrival and departure days?) Or just Ireland.
Ireland......It is small and easy to get around. Dublin 3 full days, and make a counterclockwise trip. e.g. Dublin, Glendalough, Blarney, Killarney, Dingle, Limerick, Cliffs of Mohr, the Burren, Galway, Newgrange, Knowth, Tara..........Lots of options, and this doesn't even include Northern Ireland. To me, the countryside and towns outside of Dublin are the real attractions. Ireland will fit your desired mix. Distances are short between many of these locations. You could go clockwise as well. We did a very similar trip in 2004 in 12 days and never felt rushed, traveling at a relaxed pace.
With the three countries you will lose a day going from Ireland to Edinburgh and another day from Scotland to London.

I agree with others- I would pick either just Ireland or just London/Edinburgh with that time period. If you really wanted to see all three, however, I think you can- I would then fly into Dublin, spend a few days, fly to Edinburgh (about an hour plus airport time), spend a few days, get the train down to London (about 4 hours), and then after a few days fly home from London. I think trying to fit in Galway you'd be spending most of your time travelling between places. Good luck with your planning!

We have visited the UK and Ireland several times. There is a lot to see.

Your plan is possible, but you are generally focusing on the major cities, which tend to be more expensive and ignore the beautiful scenic countryside of those islands.

It could be that this is your first time for these lands. Still, consider that with less travel, you will have more time to visit key sites.

Example, we took a tour of Ireland (not including N. Ireland) last Summer that was 10 days. We visited Dublin, Galway, The Cliffs of Moher, The Ring of Kerry, key sites along the way like Cork and the Blarney Castle. It was a Gate 1 Tour and great.

The countryside of Ireland is amazing consider doing all of your 11-12 days in Ireland and N. IREland. If you prefer the UK, then do London, but visit key places like York, Hadrian's Wall, Bath, Stonehenge, Stratford Upon Avon, Winchester, Oxford, Canterbury, Cambridge. Scotland is great, Edinburgh, Glasgow, Inverness, Loch Ness and more.

Also, London has much to see, but it is crowded and many key sites must be booked in advance. Consider a group tour that takes care of planning all those bookings as well as lodging, transportation, etc.

If you do the tour on your own, for Ireland, you will need to book a rental car. Also, for the British countryside, a car is best, but you don't want a car in a large city like London or Edinburgh. Traffic is awful and parking expensive and hard to find.

For economic lodgings in the UK, check out Premier Inn.