Time allotment for Book of Kells and Kilmainham Gaol

You'll need to book ahead for Kilmainham Gaol if you want to guarantee getting in - website: http://kilmainhamgaolmuseum.ie/
If you're willing to forget one of them, I'd vote to forget the Book of Kells. It's interesting, but usually crowded, you walk around the display case, where it's opened to one page. And that's about it. Go to the Long Room in the Trinity College Library, that was way more interesting to me.
I'd suggest just taking a taxi or walking to the Gaol and visit that first. Then, the next day try for Trinity College and Book of Kells if you really want to see it.

We were just on a RS tour in May and did both of these...The Book of Kells was pretty disappointing and seeing it didn't take much time at all but we did have tickets in advance purchased by our guide. The library is gorgeous and worth walking through but I don't think the whole experience took more than an hour. We also did a tour at Kilmainham Gaol which didn't take much longer than an hour either. Someone else maybe can tell you how long it takes to get there, it seemed to me pretty quick. I think you could do both of these activities pretty easily and still have time for a Guinness :)

Definitely the Gao! In my opinion. Have been there three times and it is still fascinating. Would not walk there take a bus and get the latest time slot and I believe you need to get there maybe 15 minutes early and be sure to book tickets n. Good luck. If you have time you can do the Book but I really enjoyed walk over the Hapenny bridge and the GPO more than the Book of Kells.

Thank you all so much for such a quick response! Y'all have confirmed my speculation that the Book of Kells may not be as exciting as I've heard--I think they may have been thinking of the library and not the actual book. Looks like we will attempt the gaol first and then see how it goes from there. I do like the idea of the Hapenny bridge and just strolling around and having a pint somewhere! Thanks, everyone!

I didn't go to Kilmainham. I'm not interested in 20th century Irish history as much as pre 1200 history. The book of Kells doesn't take long if there isn't a line. You see the book then upstairs to the library. If it was free, you'd probably go through in 15 minutes. Since you pay 14 euros, you kind of feel you need to take longer (especially if you stood in line for an hour). I think it's worth paying an extra euro for the 30 minute student led tour of the campus.

I agree that the BOK was not really worth the time (although we loved the library!). We saw more illuminated manuscripts at the Chester Beatty library (no crowds and free!). Kilmainham gaol was definitely worth the time! After the guided tour, we spent another 45 minutes walking through the museum exhibits.
Trying to do both in one afternoon may be a bit of a stretch (KG was about 30 minutes away from Trinity college. We used the Luas system and had a 15 minute walk from the Luas stop to KG, but HOHO may have a closer stop.) If you do one in am before leaving Dublin, depending on your transportation to DUB, perhaps BOK would be closer and easier. Make sure you get tickets ahead of time and factor in being at DUB 3 hours before flight.

When we did the Book of Kells, we did not make advance reservations. We simply got off at that bus stop and stood in a line that was long but not unbearably so.

I enjoyed seeing this, but unless you need to read every placard you can do this in a short amount of time. (I would budget an hour to make sure you see/read enough. Gift shop time is extra, IMO.)

Hope you have a wonderful trip!

Our flight landed in Dublin at 5am local time, so by the time we dropped our bags at our hotel and walked to the center of town for breakfast, it was only like 7:45am when we were done! Haha! We walked around trying to find things that were open that early, and we ended up at Trinity College around 8:45am. I thought we were in the wrong place because there was literally not a soul in line for the Book of Kells. We went right in, bought tickets, saw the exhibit (not very interesting in my personal opinion), went into the Long Library (much more interesting and worth the ticket just for that), then we were done and out by 9:30am. :)

Thanks, everyone. After rechecking our flights, I realized that we fly out the next day at 9am, so we are going to try to squeeze both in on that Thursday. We plan to leave Galway around 6am, giving us plenty of time to get to our hotel in Dublin, drop off our luggage, return our rental car, and then hop public transport from the airport down to the City Centre. (My husband had me change our hotel to one closer to the airport so we won't have to worry about the next morning.) I went ahead a purchased tickets for Book of Kells for a tour at 2pm, and hop another bus to the Gaol for a tour at 4. From what everyone is saying, we probably won't spend much time at Trinity college, but everyone here keeps telling us we have to see it, so we will. Lol! I'm hoping I'm not cutting our time too close to get to the Gaol. After that whirlwind, we'll probably end up at the Guinness Storehouse and drink a pint or two!