Hi Susan,
Such a shame I won't be in Edinburgh until next year as I would have loved to meet up. Hope you have a fantastic time. I wrote a quick 2 day Edinburgh guide a while back for someone, a slightly edited copy of it is below.
One thing concerns me though though- having your full name and precise itinerary including hotel addresses and dates on a public forum is a hell of a security risk. Surely just having cities and dates is sufficient for any SCF members you know who earnestly want to meet up? They can PM you to exchange contact details.
If you only have 1 day in Edinburgh I'd actually advise against visiting Edinburgh Castle- the queues this time of year can be 2 hours long, it's expensive (about $22CAD each) and to be honest the sheer number of tourists packed into it can pretty much ruin the experience.
Instead I'd suggest walking up to the castle (which is in the highest oldest part of Edinburgh universally known as the Old Town), but rather than go in just take a few photos from the outside and turn around and walk down the Royal Mile- keep visits to the plethora of tourist shops to a bare minimum (they all sell almost exactly the same stuff anyway so if you been in one, you've been in them all) and spend your money on some good Scottish beer (or whisky) in some of the unique old pubs instead! "Deacon Brodie's" pub is excellent and on the exterior is the interesting story behind it's namesake: the real-life figure who became the inspiration behind Robert Louis Stephenson's Dr. Jekyll and Mr. Hyde. Take a right onto George IV Bridge and walk straight ahead to the Museum of Scotland (free)- two museums in one: a fantastic 150-yr-old building with a very impressive cast iron and timber glazed roofed atrium which is brighter than you would ever expect of the Victorians and a wonderful extension built about 10 years ago by Benson & Forsyth Architects- easily my favourite modern building in Edinburgh. The view from the roof terrace is spectacular- especially back towards the castle. Both buildings house fantastic collections of both Scottish and imported artifacts.
Walk back up George IV bridge and meander down the Royal Mile ending up at the Queen's home when she's in town: Holyrood Palace and Enric Miralles' Scottish Parliament... the jury's out on the latter, I love parts of it and really dislike others- it's a very complex design. I've never met an Edinburgh taxi driver yet who liked any of it. All in all that should take you a long morning depending on how much time you like to spend in museums, if any.
In the afternoon I'd strongly recommend the National Gallery of Scotland (free) on the Mound (road that twists up from the grid-plan 250-yr-old New Town to the Royal Mile- aside from a good restaurant which would take care of lunch it has an excellent collection of Impressionist paintings displayed in very bright homely galleries above the more imposing blood red velvet walled main galleries on the ground floor. A free bus leaves every 15 mins between all the national galleries in Edinburgh so you could jump on that and head down to the Scottish National Gallery of Modern Art (free) and check out a few Picassos, Warhols, etc and a small, but very good surrealist collection or take a taxi down to the Botanical Gardens (free)- which are amongst the best in the world.
For a quiet, but perfect Edinburgh night out any day of the week Kay's Bar (39 Jamaica Street) in the New Town is one of my favourite pubs in the world:, absolutely tiny, great beers and whiskies, real coal fire, no food in the evenings (lots of excellent restaurants nearby), well off the tourist trail, no music, just a genuine mix of older regulars leaning against the bar and younger Edinburghers who know where to go to get away from it all and get a good pint.