No - you can buy tickets online or at the visitor’s center. I’m an American, and didn’t need anything special. Just bought the ticket online and showed up!

They are only at the visitor center, at least when we were there in February. The visitor center also has a small cafe.

I think that you will have no problem visiting the site in May as it's the peak season and the covid restrictions are being lifted now. I think the website has a 3 month booking system for tickets to allow for the numbers to visitors to visit.

If I remember correctly, it was approx. 7 Euros/person.

Ciao, la visita, dal centro visitatori e ritorno, dura circa un'ora e mezzo. Tieni però presente che, essendo le visite a numero chiuso, in base all'orario di arrivo al centro visitatori, potresti dover attendere anche un'ora il tuo turno.

I don’t know when you plan to visit Newgrange. Currently the visitor Centre is closed for renovation until about October so online ticket sales are not possible.

I’m not sure but yours are very frequent so you’ll always get a ticket no worries

To get into Newgrange is a tight squeeze. With any stroller or gear you wouldn’t get in at all and I’m sure they have more info and restrictions on their sight. The walk around the sight is doable though as it’s open. Hill of Tara is all outdoors and in fields with no pathways. Again, I wouldn’t suggest a stroller unless it has 4x4 and Hill of Tara is all outdoors with no escape from the elements. You can visit either on your own. Newgrange won’t guarantee access as bus tours get first shot, but I’d guess this time of year is fine. Hill of Tara is best to do with a tour so you get the history, but a nice walk anyway. Good luck

As above - good answers