Julianstown to Lismullen is a nice drive, about 25km of fast sweepers with excellent sightlines and a lovely surface.

It's the best driving road I've found in the North Dublin(ish) area in the years I've been spending around Balbriggan.

https://www.google.ie/maps/dir/53.67...a=!4m2!4m1!3e0

It never seems to get much love, but I'm a big fan of the R116 starting at Taylor's lane and ending at Glencullen, before taking the Ballyedmonduff Road to Step village.

https://www.google.ie/maps/dir/53.28...17d694!1m0!3e0 (unfortunately a road closure has ever so slightly buggered it up, but the Mount Venus Road is lovely to attack in the dead of night).