The Royal Mile walk was actually much more than that and included a visit to the Castle and ended at the National Museum of Scotland with the guide taking us to a few exhibits to continue to discuss Scottish history.
Our tour stayed at Brooks Hotel in the Fountainbridge area. Some of the tours stay in the New Town area so I assume their tours see some different things. Our guide walked us thru the Toll Cross area then by the George Heriot school to the Grassmarket area. Up some steps to the Royal Mile and in to the Castle. After our time there, we walked down the Royal Mile to about the St Giles Cathedral area, zigzagged around a bit, came across George IV Bridge past Elephant House (where J.K.Rowling did some of her writing) and ended at the National Museum going up in the new area with the Scottish History collection. This was by far our longest walking day.
We did go over to "tour" New Town before dinner but really it was just walking down Rose St with the guide pointing out places for coffee and lunch which didn't seem helpful based on where our hotel was located. In my eval I suggested that for future tours staying at Brooks perhaps they might have a better "neighborhood" orientation walk. IF your tour is staying in one of the hotels near or in New Town the walk would be perfect.
I traveled with my brother and SIL and we were in Edinburgh several days ahead and a couple of days after the tour. On our first pre-tour day we walked the Royal Mile and my brother spotted a shop with Harris Tweed. He tried on a vest liked it but decided to look at other places along the tour. He is NOT a shopper so I was surprised he was considering it. He did not find better prices or a nicer vest so came back to purchase it in the end and yes, he has worn it all winter. Frankly I was worried because we were pretty much tourist central but the items were all gen-u-ine Harris Tweed and the staff in the shop was very nice. This might be more expensive than you want though.
Altho I also am not much of a shopper there were cute shops all along the tour. St Andrews is filled with them and you have a couple of hours there to see the sights. On that day you'll stop at Culross House (very cool) and there are some neat shops nearby. There are shops at nearly every major site including the Crannog! There was a very cute shop at one of our rest stops that had funny Highland Cows on items. My SIL got a cute shopping bag but neither of us can remember where exactly that was. Don't worry. There are neat places all along and I'd pick things up as you go. You'll have plenty and not have to get stuff at the airport. Oh!!! I am NOT a whisky drinker but I tasted some whisky with honey at one of the shops at Stirling Castle and wow! I bought a bottle of that to bring home and it's still as good as on that chilly, rainy day!
Have you read any of the Alexander McCall Smith 44 Scotland Street series? It's so funny to visit Edinburgh and walk by locations he mentions.