You can rejoin the hurly-burly of the A90 for the return journey south from Montrose or Brechin; the more pleasant route, however, leads southwesterly on minor roads (there are several options) that travel along the face of the Grampians, following the fault line that separates Highland and Lowland. The Angus Glens extend north from points on A90. Known individually as the glens of Isla, Prosen, Clova, and Esk, these long valleys run into the high hills of the Grampians and some clearly marked walking routes. Those in Glen Clova are especially appealing.
Be aware that Thursday is a half day in Angus; many shops and attractions close at lunch.