I'll be spending a few days in London but would then like to take a train/ferry to Dublin where I want to pick up a rental car for a few days. Is this a hard, complicated process, particularly once the ferry lands and I'm tasked with not only getting into Dublin but then also finding a car rental agency? Anyone else done this and have some tips/tricks to make the process mostly painless?
No, it's neither hard nor complicated. Everything you need to know can be found here: https://www.seat61.com/Ireland.htm
Fly.
Far easier and let me say your first look at the Emerald Isle from a plane window will have you saying “WOW, it really is that green!”
Dublin airport is a modern and easy to navigate. If memory serves my Hertz rental desk was about a 10 minute walk from the terminal.
I am also going to suggest flying. The ferry's can be cancelled in rough seas. And flying is a lot faster.
Yeah, I did the train from London to Holyhead / ferry to Dun Laoghaire trip once (return) and swore that I would never do it again. Flying is much better, and once at Dublin airport, many choices of rental cars.
Only reason to take the train would be if you really want to see North Wales on the same trip.
Thanks, everyone! I never think about flying in Europe because I'm so used to flying being so expensive and painful here in the States. Good idea, though, and clearly the better option for this itinerary.