North of Liberia, the 50,000 acre Parque Nacional Santa Rosa has numerous dirt roads passing through this tropical dry forest. The forest is dominated by scrub brush with a few short trees which suit this dry, arid climate. Many of the OHV roads are up to 20km long and are shared by hikers, mountain bikers and horseback riders, as well as off-highway vehicles.
Located about 38km north of Liberia on the InterAmerican Highway, this national park is divided into two sections: the Santa Rosa Sector and the Murciélago Sector.
To reach the Santa Rosa Sector from Liberia, head north on the InterAmerican Highway RUTA 1 for 34.1km to just past milepost 169. The entrance is on the left. Turn left into the park on a paved road passing through the guard post paying the entrance fee. Continue west on the rough paved road for 7.2km from RUTA 1. Watch out for iguanas running across the road. At this point the paved road ends and trails or dirt roads begin.
From the end of the paved road, there is a steep, challenging 4WD trail heading west for 13km to Playa Naranjo. If you plan to take a motorized vehicle on this dirt road, the rangers require you to sign a waiver at the guard station. This route is shared by hikers, mountain bikers, and horseback riders (it is open to vehicles during dry season, though many people get stuck). Keep an eye out for tapirs at water holes and crocodiles among the mangroves. Note: it is closed during turtle nesting season. From the beach at Playa Naranjo, the Sendero Trail is a nice 13km hike along the beach and woodlands to Witchs Rock. Also at Playa Naranjo, the Sendero Carbonal is a 20km trail that cuts inland on the way to the beach at Cerros Carbonal.
The Naked Indian loop trail (1.5 km) begins just before the house and leads through dry-forest woodlands with streams and waterfalls and gumbo-limbo trees whose peeling red bark earned them the nickname "naked Indian trees." The Los Patos trail, which has several watering holes during dry season, is one of the best trails for spotting mammals. The Laguna Escondida and Caujiniquil River Trail (14 km round-trip) also takes you to a pond that is a magnet for thirsty wildlife. Other good spots for wildlife are Platanar Lake, Laguna Escondida, and La Penca, reached by trails north from the park administrative area.
The northern Murciélago Sector is located near Cuajiniquil off the InterAmerican Highway about 10km further north of the other sector.
Here are some basic notes on driving in Costa Rica for the tourist. There is a myth about the quality of the roads and of VW bus sized pot-holes. This may have been true years ago, but on the main routes, this is no longer true. With that said, there are still numerous challenges for first time drivers in Costa Rica. First, do not expect much out of so-call “highways”, like the InterAmerican Highway. The fancy name makes the uninitiated think this is a major 4 lane divided, restricted access road. Well, yes, about 1% is. The rest is two lane (marginally), undivided, rural roads with tons of traffic constantly stopping, turning, passing or driving slowly. Like every other road in the country, you can expect to see on the road numerous unexpected cows, cyclists, pedestrians, bus stops, school crossing zones, dogs, mud slides, police check points, unannounced one-lane bridges, missing manhole covers, and, of course, a never ending stream of semi-trucks driving erratically fast. What you do not find on any roads is much signage. There are infrequent signs indicating the distance to the next town, and even more infrequent are road names or numbers (if at all), including even within major towns. To make matters worse, signs that used to exist are disappearing due to deterioration or theft. Also, do not expect drivers to use their head lights, even in a heavy rain shower, unless it is really dark. This makes passing in rain a game of roulette since you can't see the oncoming traffic. Speaking of dark, do not drive at night since the roads in some areas can be ruled by those under the influence of alcohol.
If you have to drive through San Jose, make sure to do it at dawn to avoid the horrendous traffic all day long, including weekends. Keep in mind several maps show highways passing through San Jose. This is not true. They end abruptly on the outskirts of town and you have to slug it out in a crazy stop-and-go traffic and many unmarked turns to get to the other side all day long. There are unsigned so-called by-pass routes around San Jose, but finding them can be a challenging game of trial-and-error, and they are only marginally better.
If you have to drive on the Nicoya Peninsula, you can expect to find generally better roads with better signage. However, there are numerous unmarked eroded road sides, especially over stream culverts. Do not drive at night. Watch out for the iguanas sprinting across the road.
A GPS unit can be helpful when navigating roads, however, the maps in Costa Rica were created using a special map datum. This datum is not usually available on GPS units but the road base maps were created with it. Therefore if you use the default WGS84 datum with a base road map on the GPS unit, you will always show a position being about 0.5 miles to the north of the road base map.
When picking up a rental car, make sure to check all the tires for wear, check the spare tire pressure, check the tire jack, and make sure to test the lock on the spare tire. It would be wise to quickly purchase a can of Fix-A-Flat.
Overall, Santa Rosa National Park is the 1st most popular OHV & 4wd jeep trail of all 2 OHV routes in Costa Rica.