How to retire in Ireland from the United States.

It's a valid question, but the financial emphasis you place upon it reminds me of the fellow who asked about the length of a piece of spaghetti.  That depends, surely, upon the infernal machine. Being Irish, and having lived in the USA for many years, I have to also carefully proceed with plans to make such a move. Sure, we have to carefully look at the greenbacks. In my humble case, looking to move to the West of Ireland, and rural indeed, I know I can afford a modest lifestyle, and I'll buy a place outright and be done with that. And a fine used motor vehicle, and I'll be off scaring the Bejayzus out of everybody, including myself, on the wrong side of the road. I might knock over a Stop sign or two, but I won't starve. As far as I can see, if I can afford Texas, I won't be panhandling in County Mayo.
But a more important series of questions occupies what passes for my tiny mind. To wit, Francis, you daft old fart, is there indeed another novel or two inside you? I don't know. I have to try. And after all that sunshine you're used to, are you sure, lad, that the mist and gloom of Old Ireland won't be a shock to your system?  And are you content to gaze out of rain spattered windows, on a damp and chilly day, with the wind ah-pullin' and ah-tuggin' at every unlucky obstacle that dares stand in its way? I don't know. I have to try.  I've been in the USA 17 years now, and I've also worked in Africa and Papua New Guinea. It's been interesting, but it was never a home. Just another temporary bivouac. Somehow, the more important question fluttering through my tiny soul is the wonder if, just maybe, one day I can at last come home. I wrote a story once about what I saw from the window of a tiny cottage on the coast of County Kerry. It's called "The Little Bird off Slea Head" (writersharbor.org/work_view.php?work=471). Although that was written way back in 1982, I know that fundamentally, nothing has changed since. Isn't that odd, you might say. So in answer to your question, sure, the money is important, and it might even be "worth it", but the true value of your move, and mine, rest more in the nature of our own individual spaghetti machine. The infernal thing, you know.