No one should delete comments, I like everyones input it has helped me planning many trips :)
To some of the questions above. We sleep just fine on trains, and can sleep anywhere :) We had considered Bath for a day trip but some of things there didn't really interest us or the kids who are 12 and 15. We are doing Windsor and Stonehenge on a day trip while in London also. My wife and I have done those all day excursions and while we didn't do everything in great detail we were glad we did it. We are in the mindset of we would rather see it then not see at all. We are all healthy, athletic and love being on the go trying to fit things in but also being realistic that we won't see everything in Edinburgh but that doesn't mean we can't go back. We just don't know when we will be back. Bummed that Holyrood won't be open and looks like the Cathedral is closed and not sure when it will be back open.
On the Caledonian Sleeper on the way back I was thinking of taking that on the way back to London as it would be more comfortable and we can sleep horizontal. And be rested, then getting back at 1am to Kings Cross and then going to our hotel which is near St. Pauls Cathedral. But I get if we get done with all the things we wanted to see by dinner, we don't have to kill 3 or so hours to wait for the Caledonian to depart. If we don't do the sleeper train on the way back. Is it easy to get tickets at the train station before departure even though it may be a little more on the day of on the LNER Train?
April 8th our plan was to see the British Museum in the Afternoon and have a lazy morning in London before we fly out back home on Sunday April 9th.