Thanks so much! Can I buy a good map in San Jose?

Roadadvisor is correct, it is an easy drive South to explore Hacienda Baru, Dominical, Uvita and/or Parque Ballena. Its a great hwy and only around 30 mins driving. Also, free maps are given to you with your rental car, as well as your hotel will send you specific driving directions when requested. You can also explore local Beisanz Beach where local families go. From your hotel go towards the park, turn right where there are signs for Hotel Parador, Hotel Makanda, etc and follow this little road almost to the end. You will see a little sign for Beisanz. Its a few minutes to hike down to the little beach cove where they rent kayaks and snorkel equipment. Enjoy!

About an hour south there are two waterfall systems that are well worth a visit. Nauyaca is a great horseback ride and you can jump and swim. Nearby, Tree of Life offers some of the best canyoneering and waterfall rappelling in the world on the Diamante river.

Check amazon dot com for a good map before you go. They're difficult to find in Costa Rica although if you're staying in San Jose you can stop at seventh street books - on seventh street (calle siete) just north of Avenida central in Barrio Amon. Not only good maps but the best selection of natural history, wildlife and other books for visitors that you'll find anywhere in Costa Rica. I could (and have ;-) spend hours browsing there.