Another option..............hire a driver (or drivers, if one does not cover all the areas where you want to travel). How does one find such? Ask the B&B(s) or Inn(s) where you will be staying. We were in Ireland (I think it was 11 years ago), and we had the most fabulous driver who had a large van. He was recommended by a B&B in Doolin (his family started McGann's Pub, but I am 99.9% sure he has now retired from driving others. Ahead of time, we connected, and I sent a map/outline of what I thought we wanted to see and my guesstimates of timeframes...but with it, I included a note that we mostly just wanted him to show us the beauty of his country......he asked if it would be okay to telephone me (ahead of the trip) and we chatted, and he made some recommendations for alterations that absolutely made sense. Then once in Ireland, he made a few little changes (with our permission) and included some absolutely delightful surprises along the way (I could go on for paragraphs about those).
When we stayed two nights at certain locations, he just took other day fares then. When it made sense for him to stay in the town where we overnighted, he handled his own overnight expenses.
When I returned home, being a #s person, I compared the cost of having him (and then another driver do a one-leg journey from Tubercurry to Shannon)........but I compared that to the cost had we rented a vehicle (gone thru the stress of driving on the wrong side of the road and finding our way, not to mention the benefits of having a local drive) along with petrol............and drumroll.........it was signficantly less expensive to do what we did. There was not one day or one hour that we regretted not having a rental vehicle.
We also recommended him to friends of ours, who had an absolutely delightful time with him, and then we also hosted him for dinner in our home when he came to the states (which was extra fun).
So, such discoveries like that are absolutely possible........and, the extra benefit is that he could tell us what we were seeing along the way, or ask if we might like a quick detour to see such and such. He learned from us that we had been to Antarctica, so he surprised us with a stop at a pub where Shackleton is from...and he insisted on "buying us our first pint." My husband was fascinated by the fairy rings, and the next day, Tony arrived with a book about them as a gift for my husband, and on and on and on.
I love gardens, so we made stop at a lovely place that had expansive gardens, but I knew I also wanted to stay on schedule to make it to our next accommodation before nightfall, so I asked that he keep me on schedule and MAKE US leave in one hour...............he found us and just showed up...........and we stayed on schedule..........otherwise, I would have enjoyed the gardens way too long..................
Yes, we gave him a very nice gratuity (and even with that, it was still much less expensive than a rental car and petrol). Likely there are others like him.