I had a really nice stay at Valerie's place in Sutton. Valerie is a really nice person and good host, she is happy to give you some good advice and is very flexible and discreet too. The room is really lovely and well decorated, the big bed is really comfy!
About the location, it is really ideal if you want to stay a little bit away from the city centre but still be able to go to the city centre quite fast. The DART station is a 5 minutes walk away and the DART brings you in the city centre in 20 minutes. The service is frequent.
The fishing village of Howth is only 5 minutes away with the DART and is a beloved place for a day out of the city : there is a beautiful cliff walk there, a castle, cute restaurants...
I would gladly come back here if I am back in Dublin, thanks again Valerie!