*Admins - feel free to move if in wrong forum*

I've been roped in to walking a friends two dogs whilst he's away over this weekend. They're two ridgebacks and enjoy a decent walk, one will run off the leash all the way (if appropriate) but the other has anxiety issues with other big dogs so he stays on the leash unless I'm absolutely sure there's nothing else about.
Usually, I take them somewhere local to the west of Edinburgh, so Corstorphine hill, Crammond, Almondell/Bangour but I'm looking to take them further afield, preferably a circular walk 10+ miles with a plenty tracks off-road. I've had them up at Tentsmuir & Loch Ard but wondering if the .netters had any other suggestions, anywhere within 90 (or so) minutes of the City?