We'll be driving from Dublin Airport to Kinsale. It will be our first driving day but not our first day in Ireland. My question is: Should we go to Powerscourt the day before we drive or inlcude it in the drive? I'm a little unsure of the time it will take to get to Kinsale as I've never been in Ireland before and I want to account for getting lost and accustomed to the roads.
Thanks in advance!

Chevre, visit Powercourt in the morning, pack a pic-nic lunch and eat at the waterfall nearby. Then drive to Kinsale. I think the drive is less than 3 hours....its been a few years so I don't remember exactly.

I'd recommend going to Powerscourt the day before. I recall that we spent enough time there that we decided to stay the night in Wicklow and then went to Kinsale the next day.

It probably depends on what kind of traveler you are, but I don't like to drive for three hours, especially when I'm not used to driving on the left.

Depends on your routing and taste.

As Peg said, there is more than the castle and gardens. A tour through the Wicklow mountains/ Glendalough can easily be combined with Powerscout and is a full day trip IMO (by time you spend sightseeing, not driving).
If you want to follow the coast from Powerscout to Kinsale, 3 hours is a bit optimistic from Powerscourt IMO.

But if you went straight from Dublin next day to Kinsale, you could take the direct route to Cork (N7-N8/M8). Most of the former N8 has now been upgraded to dual carriage motorway M8 which makes driving less stressful (and faster) than on a regular highway. Cashel and Cahir are on the way to Cork/Kinsale and make a good place for a stopover.

Once you get in the vicinity of Cork, probably the easiest way to find the road to Kinsale is to follow the signs for Cork airport/ airplane pictograph. The road that leads there goes on to Kinsale.

Kinsale itself still had a bit of road construction going on at the waterfront in May. So that made it look a bit less charming. But only a bit.

P.S. Just noticed that you will pick up your car at the airport. Since you will probably be using the M50 around Dublin to get either to Powerscourt and/or Kinsale, don't forget to stop somewhere along the road at a gas station (or other establishment) that sports a "payzone" sticker to pay the toll for the M50 by 8pm the following day.

Hmmm- I've been following the Ireland site for over 6 months and I think this is the first reference I've seen to the payzone sticker? Does this apply only to the M50 belt around Dublin or to other roads elsewhere in the country??

You can also pay the toll (also in advance) on the web or via phone. But for the traveling tourist it may be the easiest way to pay when you fill up somewhere or get groceries.
The M50 toll cannot be paid on the spot because there is no toll plaza but the cars get registered by cameras.
I don't know if there are other tolled sections of the motorways where you also cannot pay cash as you go there. The tolled section of the M9 towards Cork has the option to pay cash.
The "payzone" sticker is just a sign at gas stations, grocery stores, or other locations where you can pay, among other things, your M50 toll.

Thanks, Cowboy! Do you know at what point the M50 becomes the M11? Exit 14? Exit 17?

I'm trying to figure out if I'll have to worry about that toll if I come into Dublin from Powercourt -- I'm basically following the N11 all the way in, but part of the time it's dual carriageway, i.e. M11, that eventually (after I get off at exit 17?) - hooks up to the M50

No worries, the toll section is between exits 6 and 7 in the NW section of the M50.