The N59 is a great, scenic road to drive, especially if you take the route from Ballina via Bangor, Newport, Westport, Leenane to Clifden.
If you go that way, you really should play the Wild Atlantic Dunes at Carne. But you also pass the really cool rustic 9 at Mulranny. You should stop at Westport (brilliant town) and if you are feeling really energetic you could climb Croagh Patrick.
This adds a little bit of driving to your route (which is over 4 hours direct). If you are going direct for the second half of the journey, stopping at Strandhill (half way down) for a game is a good option. Rosses Point the other option.