By air to any of the main airports, and then by car. Take a look at:
www.aerlingus.com
www.ryanair.com
www.aerarann.com

Approximate driving time without any stops:
From Dublin: Via Cork 4.5 hours and via Limerick 5.5 hours.
From Cork: 2.25 hours.
From Shannon: 3 hours.
From Kerry: 1.25 hours.

By ferry to Dublin, Rosslare or Cork. Take a look at:
www.irishferries.com
www.stenaline.ie

Approximate driving time without any stops:
From Dublin: As above.
From Rosslare: 4.5 hours.
From Cork: As above.

Nearest Airports: (i) Kerry - 63km (ii) Cork - 120km (iii) Shannon - 156km (iv) Dublin - 356-376km
Nearest Ferries: (i) Cork - 126km (ii) Rosslare - 274km

All the major Car Hire services are available at the Airports:-
www.kerryairport.ie
www.shannonairport.com
www.corkairport.com
www.dublinairport.com