We sampled a little of the Green and Gold highlights of Costa Rica.
The Green: the wonderful nature and forests of Costa Rica and its reputation for eco-tourism.
The Gold: We started our trip with a visit to the Gold Museum in San Jose, and ended the trip with 3 days along the Gold Coast (the northwest Pacific beaches). Costa Rica has some gorgeous beaches, with relatively little development on most of them. With our rental car, we were able to explore several of them.
More green: we visited Costa Rica during its Green Season (their euphemism for rainy season). Airfares and hotel rates are slightly lower at this time. The rain didn't really interfere with our enjoyment of the country and activities at all. It typically rained in the afternoon, so we just planned our main activities for the morning, and the afternoon rains usually came when we were returning from our day trips or were just resting up. There were a few days that we woke up to very hard early morning rainfalls, but they passed by quickly.
Quick Tips:
Plan outdoor activities for the morning and try to get going early. We drove up to Poas Volcano and had a clear view all way up, but by the time we got to the crater (about 10:30 a.m.) the crater had filled with clouds. (It was still worth seeing.)
Most rental car companies will deliver to your hotel around San Jose, saving you the airport surcharge.
From volcano watching, to jungle boat tours, to zip-lining through the forest canopy, to just chilling on the beach, there a plenty of activities to keep you busy in Costa Rica. Most of the big activities like zip lining or white water rafting are pretty expensive, so if you're on a budget, you'll probably have to pick which things you like best.
They really do accept US dollars just about everywhere. Credit cards are also widely accepted.
Can you drink the water? Costa Rican tap water is supposedly safe. I drank it frequently and had no problems at all. My wife and kids weren't super careful (brushing teeth, ice in drinks, eating things like lettuce) and also had no disease problems. Best Way To Get Around:
We rented a 4WD Gran Vitara. It was very convenient getting around with our own car, and driving wasn't too bad, as long as you aren't in a hurry. With narrow winding roads, some slow trucks or buses, you're doing well to average 60 kph. Despite how close destinations look on a map, it takes a lot of time for most drives here. Road signs for directions weren't always very good, with some of them pretty small and easily missed. We managed to not get lost. At the Pacific beaches, there are lots of big signs pointing you to the bigger resorts and beaches.
We hired a driver to take us into San Jose from our hotel in Alajuela. We considered it money well spent since the traffic was really horrible, it was pouring down rain, and we would have had no idea where to park.
The big debate in renting a car in Costa Rica is 4WD vs. regular car. We went with 4WD, but in retrospect, it really wasn't necessary and we could have easily saved our money by going with a regular car. Most roads were paved on our drives from Alajuela to Arenal to the Pacific coast. There were three or four exceptions: 1) The 9km lane to VillaBlanca which was in pretty good shape. 2) The very rutted road up to the top of La Fortuna Waterfall. 3) The road to Arenal National Park and the hotels there --- truly horrible and rutted. 4) (The worst) The last 3 km to Pan de Azucar Playa --- very rutted, bumpy, hilly, and slow-going.
Gasoline cost about the same as in the USA (about US 1.30 / liter when we were there in July 2008)
If there hadn't been four of us, it would have been cheaper to get around using buses, taxis, etc. There are bus or shuttle companies that'll take you between most major destinations for US 35 or less (e.g. San Jose to Arenal, or Arenal to Tamarindo or US 20 for Jeep-boat-Jeep from La Fortuna to Monteverde).