Köln-Dransdorf-Heimerzheim-Brühl-Köln

From Van Ham via Berzdorf, Falkenlust Castle (80 m tough Paris-Roubaix section) to Dickopshof. From there to Roisdorf (you already know the route) via Alfter along the railway line to Dransdorf. Right turn through Messdorf to Nettekoven from where it’s a steep climb to Buschhoven. Then roll downhill (not so nice in the wind) to Metternich, then right uphill around Rösberg, a short descent (7.5%), then continue to Sechtem. (I might get lost here). Around Brühl to Kalscheuren and from there everything’s under control again. Höningen, Rondorf, finish.

You can also shorten the whole route by about 15 km via Brenig, but the climb there is veeeery nasty. I haven’t managed it yet without stopping, but that doesn’t mean anything.