I prompted discussion a while back with a Borders Drove Road suggestion, but that path is fierce, man, and not a suitable place for anyone to start bikepacking. Ran into the long grass.
I'm now thinking of loading the trailer for a gentle jaunt on the last weekend of September. Just rumble up a glen, pitch the tent, watch the sun go down and rumble back home.
Was thinking either Glen Almond in Perthshire from the Sma' Glen or Glen Avon from Tomintoul. Both are land rover track with additional mad options for mad people.