One of the best trips involves a canyon site near Rancho La Trinidad, about 29 km (18 miles) west of Mulegé.  As with other sites encompassed by central Baja's Great Mural tradition, those at La Trinidad are federally protected and you're only supposed to visit with a licensed guide.  Viewing the major sites at La Trinidad means a challenging canyon hike of around 6.5 km (four miles) that includes several river crossings - at least two and sometimes three usually require swimming.  Although the hike isn't particularly difficult or dangerous, it requires good overall fitness, the ability to swim up to a hundred meters (300 feet) through calm waters, the strength to hoist oneself out of the water onto stone riverbanks up to a meter high, and a fair sense of balance for walking along narrow paths.

Official La Trinidad on-site guides
Placido Castro Romero
Alonso Castro Arce

You should also carry at least two liters (roughly a half gallon) of drinking water per person, preferably in canteens or other containers slung over the shoulder.  You can float a limited amount of camera gear up the river on small, impromptu rafts made of inflated inner tubes and any flat, sturdy material used as a platform over the tube.  Everything else you bring along, including shoes (Teva-style sports sandals are the perfect footwear for this trip), should be submersible.  Count on a half-day to complete the canyon hike itself, although some visitors prefer to spend an entire day in the canyon.  Others may want to spend some time at the various ranchos along the way.

The trip begins with a scenic desert drive to Rancho La Trinidad, a large goat and cattle ranch at the foot of the mountains.  Some guides stop at other ranches along the way to allow visitors to observe leather tanning, cheese-making, and other ranch crafts.  After you arrive at Rancho La Trinidad, you hike about 800 meters (a half mile) to a four-meter (12 foot stone dam, which you must climb to enter Canyon La Trinidad.  These are reportedly the headwaters of the Rio Mulegé, though the river drops underground before resurfacing near town.  Once inside the mouth of the canyon, you make one river crossing before reaching the first and largest group of murals.  Among the many red and black animal representations on the canyon walls is a large ocher dear silhouette, considered one of the best prehistoric deer paintings in Baja; others throughout the peninsula are often compared to the "Trinidad deer".  Among humanoid representations in this group is a shamanistic figure sometimes referred to as "cardón man," though there's no real evidence to suggest the image is linked to local legends about cardón cacti coming to life at night.  Arrows pierce the figure's neck, chest, and groin.  There are also a couple of vulva drawings and a painting of a fish skeleton, thought to be the only such work in Baja; other fish paintings in Baja appear to represent whole fish.

To reach the second group of murals you must ford the river several more times.  Depending on the river height, at least one crossing requires a swim of up to 100 meters through a narrow stone gorge.  For many people this is the high point of the trip.  The water is safe to swim in but should be boiled or treated before drinking.  The canyon scenery is spectacular, with cactus and wild fig trees clinging to the sides of high tuff (volcanic ash) cliffs.

The final site is reached by ascending a sloped canyon wall affording long views of the canyon, which splits in two here.  The paintings at this site are neither as numerous nor as impressive as the first, but the hike/swim through the canyon makes it a worthwhile objective.

Several guides in the Mulegé area are licensed to lead this trip.  Any of the hotels in town can arrange for a guide; the usual price is $33 US per person when using the guide's vehicle, $25 US per person with your own. High road clearance is required and a cache of spare parts is suggested.  The fee usually includes a simple lunch, sodas, and beer.  Recommended guides Salvador at Hotel La Casitas, Chichu at Hotel Serenidad, and Kerry ("El Vikingo", the only gringo guide in town - and perhaps in all of Baja - licensed to lead visitors to prehistoric murals), who can usually be contacted through the Restaurant Candil.  Most tours include an interesting stop in the desert to learn about medicinal plants.

You can drive to Rancho La Trinidad and arrange for someone at the ranch to take you to see the murals.  Although this is much less expensive - no more than $5 US per person - the drive to the ranch involves several unsigned turns.  Ask at one of the hotels for detailed directions.  The turnoff for the main road from Mexico 1, known locally as the "Ice House Road" for the ice factory alongside it, is just at the north entry into Mulegé it is signed San Estanislao.  Continue following signs to San Estanislao until you see a sign for La Trinidad.