A free shuttle bus and we went for the hop on hop off tour bus (15 euros), but there were other options. A trip to Mulahide Castle and a coastal trip was available for 25 euros and we'd have probably tried that if we'd known about it beforehand. The tour bus is almost one and a half hours round trip so you need to bear in mind what stop you are on and how far back to base you are. You can visit the guiness factory, Trinity college, everything from the bus. We opted for the Jameson distillery then crossed the bridge for the cathedral (never got there, the hill was too steep) so had to go back over the bridge to get on where we got off else it would have been another hour on the bus going round again.
Plenty of places to eat and drink, our paninis at the Brazen Head Inn were only 6 euros each and came with salad, there were two huge paninis on the plate and I struggled to eat them. Lovely though.
Didn't see tourist Info, the best bet is to look it all up on the internet beforehand and plan your day