Avoid the M1 into town - single lane due to port tunnel works and it is always backed up from Griffith avenue out to Coolock exit inbound.
My failsafe route - and I commute from Swords to town daily is as follows :
Go out back exit of airport and turn left (or else north from main roundabout to Coachman's roundabout and take a left)
Straight along back roads (passing St Margarets) to roundabout at end of runway. (approx 2.5 miles)
Straight through roundabout.
Continue on this road until you pass over M50. (approx 2 miles)
Left at next roundabout (just over M50 bridge)
Right at next junction (only 300 yards) - new houses/apartments just at junction. (you are now on Jamestown road)
Straight down (straight through roundabout) to next lights. (about 0.5 miles)
Take left at lights.
Straight down to end (T junction) - 0.5 miles - passing Willows pub on LHS
Go right and then left at roundabout. (200 yards) You are now on Glasnevin Avenue(or Ballymun Avenue - depends who you talk to !)
Straight about 1 mile until junction with Ballymun Road.
Right here and then all way down past DCU, Griffith Avenue and take left onto Home Farm road.
Take first right down to bottom by the Tolka/park.
Follow road around until you get to Drumcondra Road at Millmount house.
Take a right here and go straight down Dorset St onto Bolton St.
Go left just before Bolton St DIT and down beside Virgin Cinema and Stringfellows (stop to waste a quick 20 quid!).
Right at lights onto Parnell St.
Left down Wolfe Tone St (go down here rather than Capel St - no traffic)
Down to end past the little park (Jervis Park)
Right onto Abbey St, Left onto Capel st, over Capel st bridge, right City Hall and Sharp Left up around Dublin Castle, down Werburgh St, onto Bride St, Kevin St, Cuffe St, Stephen's Green.
Or else go left off Parliament St onto Dame St, down Westmoreland St, up D'Olier st, college green, nassau st, kildare st, stephen's green, depending which side of the green you want !
total travel time should be lass than 1 hour - you should be on Drumcondra road within 35 minutes and from there in it's anyone's guess - maybe another 25 minutes !
hope this helps.
Note - I now commute on a motorbike but did drive in for about 5 years.