11days Dublin loop- Rental Car-1st Day

I think Trinity Lodge on Frederick St. has parking available in a nearby parking garage. Not sure if the parking garage is part of the Lodge or if it is public parking. You will need to verify this with Trinity Lodge because I'm not sure how the parking works but remember seeing the garage as we were walking in the area. Location is off Nassau St. near Trinity College. We picked up our rental car in Dublin and then drove to Glendalough and other sites around Ireland. We did not need a car in Dublin. Perhaps there are places at the airport where you could park your car for a few days but wondering why you don't pick your car up in Dublin when you are ready to leave or take a bus/taxi back to the airport to pick up the rental and not pay for parking?

Anyway, I love all the places you plan to visit, but I think your list is ambitious. I wonder if you are allowing enough time to savor each place? This is from someone who spent 6 hours driving and stopping frequently on the Dingle Loop and then went back the next day to see a few sights we had missed! I find it hard to tear myself away from the gorgeous scenery and unique historical sites in Ireland.

Just a suggestion, you might consider going north from Dublin or the airport to Newgrange, Hill of Tara and then continuing on to N. Ireland. Continue to Sligo head to Galway and go through the Burren, Killarney, Kenmare, Kilkenny, Wexford (Wexford will be a bit out of your way if you travel from Kilkenny to Wexford and then to Dublin) and back to Dublin. This looks like a lot of driving to me and driving in Ireland takes a bit more time than driving in the U.S., at least that has been our experience.
Barbara

awalliskrull-a few observations:
You don't need or want a car IN Dublin. We picked ours up on our last day in town, from the Budget office on Drumcondra. After carefully planning a clean exit from the city, we took a wrong turn and got lost in Dublin. Trust me on this, get your car as you are leaving. There is very good bus trans in town.
You have a very busy itinerary, I would encourage you to be very realistic as to how fast you can-or want to-move around in a strange country where you drive on the left and the signs often do not make sense. As Barbara points out, you need to add time and lots of it to get places.
You will want to show up 30-60 minutes early for the Kilmainham Gaol tour, and you'll need 2-3 hours in total to wait, then do the tour, then see the small and very good museum at the Gaol. One hour is not enough. It's all well and good to assign 15 minites for the bridge, but you need to consider the 45 minutes to get to it from the Gaol, or wherever, and the time required to get to your next sight. The Archeological and Natural History Museums are excellent, but 1.5 hours is not enough time, imho. Don't forget St Stephens Green nearby, worth a 30 minute walk through at the least.
As for your time in Belfast, I recommend you see the fine City Hall, there are free tours there. You will not do justice to the city if you are intent on being 3-4 hours away for the Dolmen in the afternoon. You might consider a day trip to Belfast from the train station in Dublin. Take a Black Taxi tour of The Troubles areas-they can pick you up at the station.
Slow down. Pace yourself and be honest about time, and be honest about why you want to go to Ireland; is it to experience the country or is it to check a box?
And by the way-no Dingle Peninsula?
Have a great trip!

Thank you all for the advice! I booked the tickets and the car through a big box site and wasn't thinking about not needing the car on day 1. At this point I do not think that I can change the pickup date and it defaulted to our arrival time at the airport. I have left about 3 days of tour unaccounted for to allow to spend more time as we desire. We are not pre-booking hotels which may be a mistake but this will allow us to move at our own pace without having to make haste to go to the hotel that we book x amount of miles away.

I think that generally speaking you can change a car rental date. Here is a link to B & B Ireland, where you can at least see a few that may be available for a given area, having a few options along with you would be good if not making reservations.
http://www.bandbireland.com/home

You have a lot scheduled for the first day I would lighten the load. Actually every day you have a lot of stops and a lot of stops back and forth. We go every year my husband is from Cork. Day 2 if you are headed south to Wicklow I would go to Glendoulogh instead of Powerscourt. Kilkenney is not that interesting. Newgrange is an interesting place and covers a huge area. Kenmare is a great base to check out Kerry and West Cork. Definitely do not bother going to Skellig Michael. Galway during art fest is very crowded book your hotel ahead. Hopes this helps.