well id fly into dublin stay in a nice hotel,
day 2 train to cork overnight in cork stay outside city centre if poss
day 3 back to dublin full day doing guiness factory and the older bars then
day 4 train to belfast (its called the enterprise lol) overnight there (stay at the europa hotel its the most bombed building in the world
) then fly home from belfast city airport
unlike here trains are very good back home