Only you can decide and it seems like you know the pros and cons at this stage.

But some other things to consider:

Will you have to pay extra luggage charges on your domestic flight.

Is there a place to drop off the car by Killarney or Cork train station? Very few companies will allow this.

At this stage it seems like you are really trying to include as many stops as you can on your trip and so by all means drive. Just get an early start and don't delay too much and you can still make it to Dublin at a decent time. Hoping you don't hit too much traffic as you enter Dublin and can find and drop off rental before the office closes.

You're right Tony and I could be getting reprimanded by now for my excessive posts.

Im sure a bunch have already mumbled SHUT UP under their breath. But I have learned so much more from the detailed personal replies than I did from just reading others posts.

believe me, I did a ton of reading before I even posted and if not I'd have been banned by now :)

I just appreciate all the different points of view and to be honest, the more replies the more focused this trip became.

Including your very helpful posts.. which I might add I would have never gotten if I stopped posting or just read old posts. So thanks and sorry for my repetitiveness.

Even when I thought there was no more to say.. you mention domestic luggage.. see my point ;0

Cheers and Thanks

You are very welcome and if you have any other questions please feel free to ask. The other members are free to read and respond as they see fit and you are free (I have never heard of TA limiting questions as long as they meet the main requirements of being friendly and on topic) to keep asking questions.