Probably over the top road to Hillside, up to Inverbervie, Fordoun, Auchenblae, Clatterin’ Bridge, Fettercairn…. probably! Could meet you at the Co-op in Brechin (by the mini roundabout at the bottom of Trinity Rd) if that’s easier.
Link to route on Mapometer: http://gb.mapometer.com/cycling/route_3712143.html
I’ve only done as far as Fettercairn: I usually meander round the back roads by Edzell so I get back to Brechin in good time.