I've tried many ways and if you are 'searching for lost time' trust me and follow my directions.

You can take the coastal (D513) or inland route (D27) to Cabourg but the coastal route is more direct and truly lovely. 

Check out the amazing life sized dinosaur bush while riding through Villers-sur-Mer!

Either way, you can't avoid the long uphill from Villier-sur-mer to Auberville.  Just hang on and DO IT.  But remember to turn right to the D163 once you get up to Auberville.  This route is a lot prettier than continuing straight on the D513 and will take you to the  spectacular view point at the top of the Falaise des Vaches Noires.

Enjoy the downhill from Auberville in the direction of Dives and Houlgate, and smile because you won't have to return that way...How deep.  I mean...How steep.

Walk along the sea promenade past the famous Grand Hotel.  Stroll along the one commercial street in the city center.  If you forgot your sandwiches at home (yep, I did) you can buy some great bread and chocolate for an impromptu feast.

Watch out for the fork in the road on the way back and make sure to take the D513. There might also be a spoon. Watch out for that too.  Both roads mean an uphill trek to Auberville, but the D168 is true hell if you take it on your back back.

Enjoy the long downhill ride into Villers-sur-Mer and be amazed you actually rode this way up a few hours ago!   Now back along the sea shore until the Benerville hill just before Tourgeville and home.