The choices are only additions to the circuit: branches off the main circular. There were no <i>either or</i>'s in there - well, there wasn't meant to be.
I think it's possible to get to the whole of that list in a day. It really depends on how long you would want to stay at each site. My favourite approach is to blast to a load of sites and then go back for longer visits* to the better ones when I have chance, but then I'm filling a website so the 'wham-bam-etc.' method suits that best.
There are some nice standing stones on the island and if I wanted to pad it out or swap a few sites (because my route is very tomb-ocentric :-) I'd zoom into the TMA map, pick out the ones on the list and then look at all the ones in between. If they look worthy then I'd check the OS map to see how easy they are to access.
*This approach hardly ever seems to work because of the sheer volume of sites left to see in Ireland! Tomorrow I pass right by at least 50 standing stones that, should I try and return in the future to one of the nicer places I find on this trip for a chill-out, I just know I'll have to check out ...
