OK - Well I have cycled the around most of the Ring of Kerry and if you stick with the offical signed route, it is road all the way and unless they have done some major resurfacing work, the road surface is best described as irish and interesting in places - we did it on mountain bikes, but you would easily get away with a cross or a roadbike with flat bars. however if you are happier with a mtb bike and never been on drops, I would suggest now is not the time to make the change.
If you need to carry stuff with you, you need to
check the bike can take a rack first - I would seriously recommend panniers & rack rather than a rucksack because they are much more comfortable, and hold the centre of gravity lower down so you are less likely to topple over when it is least expected. 2 small panniers should be ample.
The ring of kerry has plenty of options for getting food so you will not need to worry about anything other than lunch. I would suggest you make sure you training includes some climbing work, because there are a couple of interesting climbs along the way that can appear quite daunting at first (I have done them all, and did make them albeit slowly). There is also an unofficial one way system for the coaches & tour parties who basically go anti-clockwise starting from Killarney and heading onto the northern shores of the Ring of Kerry first (Caherciveen where we stayed), so if you don't want to be constantly overtaken by coaches along some really narrow or windy stretched of road, I would suggest the other way around as an option. It was our prefered option and made cycling much more pleasant.
http://www.mapmyride.com/routes/view/517061 is a plan of the route in the "coach party" direction
I take it you are not doing the
offical 6th July cycle it in a day charity event then?
I don't know the boardman's so can't help you on that one.
