My wife and my in-laws, total 8 people, vacationed in Jaco, but we stayed at Hotel La Rosa de America our first and last nights in Costa Rica. This is a perfect place to start and end such a trip. The botanical gardens are wonderful, you can hear a little wildlife when you wake up in the morning (this can be good or bad), and the complimentary breakfast is delicious. The hotel booked us shuttles to and from the airport and provided some helpful tips on the adventures we were looking into.
Additionally, Hotel La Rosa de America helped us retrieve some overcharges on our rental car. We were overcharged $180.00 and figured we stood little chance on getting this back seeing we were arguing with a rental agency 2000 miles away. The hotel helped us out with our communications and we have received every penny back.