I have a colleague who walks from Connolly in about 20 minutes - he used to get the DART for one stop but thought the walk was better overall. There are plenty of people who get on the DART at Connolly and get off at Clontarf Road, but since there is a 10-15 minute walk from the DART station to East Point anyway it seems a bit of a waste of time to get the train one stop. Makes sense on a rainy moring though.
There is a free bus from the DART station to East Point, but it is not exactly reliable. It can shave a few minutes off the walk, but the benefit can be lost by the more than a few minutes spent waiting for it. Between 0830 and 0900 there are so many people spilling off the DARTs that there is a huge queue, but by the time I get there about 0930 there is normally no queue. If there is a bus there i get it, if not I walk.
I have another colleague who drives (a fair bit) to Red Cow, gets the LUAS to Connolly and then gets the DART. I don't know how long it takes him, but it is a *long* time.
Driving away from East Point (assuming you can get parking anyway) appears to be hit and miss. Leave it till after about 1715 and it can take a good 10 minutes just to get out of East Point. I regularly walk faster than the cars in the queue. Even when you leave East Point you aren't near any major roads that would get you in the direction you want to go - so you are subject to the random behaviour of Dublin traffic.
z