Two roads to Dingle. From the north via Tralee and Conor Pass or from the east via Killarney, Inch Beach and the southern end of the Dingle Peninsula. Both are scenic and well worth the drive. We drove into Dingle by Conor Pass and then the eastern road to Killarney when we left Dingle. But I wish I had known about the southern route on my way to Dingle, as the ceiling was low and the drive thru Conor Pass with the fog shook the bejeezus out of me.
This is an area that needs a means of transportation to fully explore. A car will get you where you want to go. There are tour packages available, but IMO they limit your experience. In a couple days you could explore by bicycle...if I were younger I think that would be how I'd want to do it!
There are two main routes to Dingle, via Inch or via Camp, both are beautiful scenic drives. The road via Inch runs along the coast with great views of the Atlantic, and also Inch itself has a nice long strand. The other road goes via the Conor Pass, with impressive mountain views. I'd recommend to come one way and leave via the other. The Inch road is definitely an easier drive though.