Not sure what your into, but when I go I do lots of castles, ruined or good, lots of historic places including abbeys, mansions etc. You will have to watch the condition of the roads though mate, the main ones aren't bad but venture off onto country lanes and you will have to keep a weather eye open not only on the roads but also on the drivers!!! Some counties have more money than others and keep their roads well, others who don't have the money spend it on other things that they consider more worthy. Beware the towns estates, they have a worse reputation than anything we have in the UK, for instance Limerick City is known to the locals as 'Stab City'. Town centres are good but don't be stopping on the estates to ask for directions. You can't tell which youths are 'good boys' or 'bad boys' as they all dress like chavs, trackies and the like.
Can't tell you much about campsites as I stay with friends or B and B it. I will say that food (eating out) is more expensive than the UK, drinking is the same. Fuel the last time I was over (May) was more pricey too.
Getting onto the toll route out of the docks at Dublin couldn't be more simple, cost me 3 Euros but I was in a car the last time, just make sure you have Euros in change and you won't go far wrong. Just follow the traffic and the signs for the toll route, M1. Going round the M50 ring road will cost you a toll between certain junctions, but there are no toll booths, as your on a UK bike I wouldn't worry about that as the last times I have been on a bike I have never paid and never been chased for the cash either.
You'll have a great time I'm sure, one thing make sure you have enough fuel to get out of the city and out onto the route your going to take, there are no services on the M50, or at least there most certainly wasn't in May.
Have fun