Steve Kidd Cycling Trips and GuidesSteve Kidd Cycling Trips and Guides
I was catching a train, it was into the wind, and it was a drag. On another day I might have had a tailwind, and had time, taken some back roads, and made it an end in itself. I would definitely take the coast road to Malin, getting better views and cutting out a hill, and before the road turns to Quigley's Point, about 20 k from Derry, I would have taken the right to go down a quieter road (although it was unmetalled), eliminating a brake on hill down to the coast. 
Google maps initially put me up the rubble track, but the second turn looked OK, but I'd lost trust.
Note to self. Make cycling the end itself, not strictly a means of getting from a to b quickly, my recommendation would be make more time and leave the main road. Why do I never learn?
As guides these things are pretty rendundant now, so two cheers for Google Maps