After 4 nights in Edinburgh and 2 in Stirling for the Highland Games, our itinerary draft takes us by train to Inverness (mid August, 2018). I see we could travel by way of Aberdeen or Perth -Blair Atholl-Aviemore. We have a night or two to spend on our way to 3 nights in Inverness. We appreciate recommendations for route with highlights noting sites, lodging and activities based on your experiences (primarily referencing Rick Steve Great Britain). Thank you for your time and guidance.
I'd vote for Perth - Blair Atholl - Aviemore. You'll get to see the the Cairngorms scenery, and there are fun things to do in Blair Atholl and Aviemore (can't speak for Perth, but probably true there too).
I have not been to Aberdeen but am told it's not a particularly attractive city from a tourist standpoint. (Note it doesn't appear in the index of the Rick Steves guide to Great Britain.) The train line does run along the coast partway but I'm not sure how much scenery you actually get to see -- perhaps someone else can comment on that.