I would look at doing Braemar out past Mar Lodge and down to Blair Athol through Glen Tilt (magic bit of ST on route), up by A9 to Dalnacardoch Lodge. Then upto Sronphadruig Lodge, Gaick (another lovely bit ST by loch) and down to Weir above Bhran cottage.
Here is the crux, we went onto down towards Kingussie, Feshiebridge round the lochs and back to Glenmore near Aviemore. BUT there is a track showing that takes you into Feshie where you can do the run up Geldie burn and back to Braemar.
We did a longer loop out through Abernethy to Tomintoul, Inchrory and past Culardoch to Braemar then onto described and we did it over a few days but I am an old fart and you young uns could probably beast it in no time.
Have been looking at a route from Glenmore, Ryvoan, Strathnethy, Fords of Avon refuge (could be well named) Glen Derry to Linn of Dee and then back via Feshie. The best bit about that way would be the fast ST round Loch Gamma & an Eilein and then Morlich at the end.
Then of course there is Skye, Arkle loop, Evanton to Ullapool via Croick Church etc.
Whatever you do hope you enjoy. 😀