Bonjour Marie,
You are guaranteed to have stunning morning views with such a tent! That sounds like a really cool way to travel!
As Rebecca said you'd need the landsowner permission to setup your rooftent overnight outside of campsites, but there are indeed alternatives such as the ones listed on the
Motorhome craic forum or even the
Britstops network (the equivalent of France Passion).
I would however prefer campsites listed
on Camping Ireland. Some of them have really gorgeous views, especially along the Wild Atlantic Way. (Look at
this one in Clifden, Connemara for instance - my all-time favorite)
Let us know how the planning goes :)
A bientôt,
Antoine