depends on level of commitment – I’m definitely in cautious XC territory.
Have revisited Aviemore for a las weekend last few years, have rarely repeated ourselves. Have headed over towards Carrbridge on scotroutes suggestion, lovely decent that way, and equally brill singletrack coming back out of Carr and by Boat of Garten. Decent singletrack by Nethybridge too.
Usual – Ryvoan – Boat of Garten – Speyside Way – Aviemore and back.
Also see Badaguish XC course – aka Canadian Trails.
Definitely – if you can – head down past Loch an Eilean, loch Gammna, and towards Feshiebridge and Creag Dhu. Some absolute belters of sections there. Highly recommended. Can see if I can forward GPX files if you can contact me.
Also pop in by Bothy Bikes, get a map of a selected area and if you get it annotated, so much the better.