Dublin is a city you leave by the back door if you are a rider, and the back door is the one that points toward the Wicklow hills. Beginning somewhere in the middle of the city, with over a million people in the area, you spend the first half hour in ordinary urban work: buses, bus lanes, cyclists, taxis, the Liffey in the distance, and traffic lights that never seem to line up. Ireland's capital is compact, friendly and slow to cross at rush hour, so leave before eight or after nine.
There is plenty to see if you have time, but since this is a start, make it practical. Fill the tank in the city, grab breakfast in one of the many cafes, and check the forecast, because the weather in the mountains can differ completely from the weather on the bay. The Vikings founded a settlement here in the ninth century, at the dark pool, Dubh Linn, which gave the city its name. Trinity College holds the Book of Kells, Guinness has been brewed here since 1759 at St James's Gate, and Joyce, Wilde, Beckett and Swift all walked these streets.
Heading south, you climb quickly out of the suburbs. Within perhaps forty minutes of leaving the centre, houses give way to hedges, then to open heather and pine forest as the road enters the Dublin Mountains. This is the beginning of the Military Road, which the British built after the 1798 rebellion to flush rebels out of the Wicklow glens. It is a good lesson in how history shapes a ride: the road was cut through wild country for soldiers, and now it carries motorbikes and walkers.
A word of caution about traffic. Weekends bring a lot of Dubliners toward the mountains, especially on sunny days, and speed enforcement is firm. Ride the Military Road at a measured pace, as sheep and loose gravel are common. It is worth leaving the city at dawn on a summer morning, when the streets are quiet, the sky is wide and the first hill appears like a promise.