Both routes from Glentanar would be runable, but would recommend going up by the track that passes behind clachan yell, as the path up to the hill from Glentanar itself, is an eroded rocky mess..
The route from Ballater is good too, but involves 1/2 a km of wading through deep heather on a very narrow stalkers path.. Nae good if you are wearing itsy bitsy running shorts - scratched legs!