The Wicklow Way

We've only done parts of the route you propose - mainly in the vicinity of Glendalough and points south - but I think it's safe to say you're in for a terrific trip.
There are plenty of online resources that describe the various sections of the multi-day walk so I won't belabor those, but having done quite a lot of hiking in Ireland in general my advice would be to 1. come prepared with quality, well broken in waterproofs, paying special attention to your boots. Many sections of the trail are likely to be boggy - even if the recent weather has been relatively dry. That's just the nature of walking in Ireland. 2. Don't forget bug repellent. Coming upon a Spring hatch of midges can really ruin your day if your not prepared. 3. We use hiking poles almost exclusively now. They're particularly handy for helping with our balance while picking our way thru boggy places, stream crossings, etc. Even with only a day pack you'll see a big difference. I use a set of Leki poles that break down into sections of only about 24" in length so they fit in my checked baggage. Don't think you can bring them in your carry-ons, fyi. 4. A good, wide-brimmed hat wouldn't go amiss either. When the sun does come out it can be pretty intense - thanks to the lack of smog, smoke and general industrial pollution in the air that you might encounter at other destinations.
You're going to have a great time.
And yes, the dialing procedure for calling an Irish number from a US phone is as you describe. Only wrinkle is to drop the lead "0" if dialing a cell phone number.

We have hiked near there, on the Spinc Loop trail. It was spectacular, and a strenuous climb. You may encounter "sleepers," which are railroad ties laid end to end with chicken wire on top for traction, especially over the boggy areas. I would also recommend poles or even a sturdy stick.

We've also done long-distance walks like the one you're planning, in England: Hadrian's Wall, and others. It's a great way to travel.

Bring snacks and plenty of water every day. Sunscreen, hat, sunglasses, bug repellent. Bandanna. You may have long stretches with no facilities for lunch or bathroom. Your cell phone may not work at all, so it'll be nice that someone will know where you are.

How many days will you be hiking? How many miles total? If possible, you might want to add a rest day somewhere in the middle. Hiking may not sound strenuous, but it has an accumulative effect, and a day off can do wonders.

Have an awesome time!!

re: Robert - all good advice, thanks. I am still not sure about the '+' in front of the 353. Does that just indicate you need the 011 or do you actually have to dial a plus sign?

re: Stacy - Thanks for your thoughtful reply. We will be hiking 3 days, approximately 17 or so miles a day. Seems long and I am sure there are some steep sections, so I have been training here in the Pacific Northwest where we have some really steep hikes. Because we have hooked up with a tour company, there will be no days off hiking, but we do have an extra day in Dublin at the end, so we figure just walking around Dublin should be rest enough before the long flight back.

The + just cues you to dial the international access code from your home country, which in the US is 011.

re: Robert - Great, thanks!

A day in Dublin after 3 days hiking will be perfect. Have a wonderful time!

If you enjoy hiking, I can highly recommend MacAdventures. They are based out of Glasgow, but just opened an office in Boulder. We used them to hike The Great Glen Way in Scotland and Alsace region in France and leave for Ireland to hike The Dingle Way in a few weeks. They are very well priced for self guided trips. Great info prior to leaving...and great service while on the trip. My hubby and I only do self guided trips now, we don't enjoy the group dynamics, or buses filled with tours.

I realize you've got your trip planned for the Wicklow Way,but though I'd let you know about Mac....you may be hooked on hiking trips like this and want some more options for companies..

Re: Ellen - great info,thanks. I type this from a tent, having fun camping

The + just cues you to dial the international access code from your
home country, which in the US is 011.

For a landline.

For a mobile you actually type the +

"For a mobile you actually type the +"
True. Just clarify for the OP, dialing the + on your mobile/smart phone automatically enters the international dialing prefix for you. Alternatively, you can do it manually by dialing the 011 ... same as you would for a landline as was mentioned.
Might want to Google the international dialing procedure if you're still confused.