On Santa Cruz in California’s Channel Islands, a traffic jam is 6 kayaks

Before I tell you about the glorious solitude on Santa Cruz Island, off the coast of Ventura in Southern California, let’s be clear that there is some congestion among the coastal cliffs and grassy hills.

For instance, if there is a sea caves tour, you might see half a dozen folks dragging yellow plastic vessels into the shallows, all at once.

If several couples decide to hike the Potato Harbor Overlook, you might meet them all on the clifftop at lunchtime, surveying the swells below.

And on weekends, when boats from Ventura arrive at Scorpion Anchorage after a 75-minute trip, you will see scores of passengers come ashore as a National Park Service ranger tells them what to expect on California’s largest island.

What you won’t find are cars. Or even bicycles.

On this island, the only way around is by foot and water, and only in designated areas.

Santa Cruz, four times the size of Manhattan and not one-millionth as busy, is one of five islands that make up Channel Islands National Park. Visitors often describe it as a vision of what California must have looked like 300 years ago.

That’s not quite correct, because the island’s mix of plants and animals is the result of generations of human importation, extermination, and experimentation. But it is a different Southern California from the one at the other end of the boat ride.

More than 10 million Californians live within 75 miles of this island. Yet on a weekend night, it’s rare to find 100 people on Santa Cruz.

On the boat trip from Ventura, you may spot one or two dolphins, or perhaps, as I did, 200 leaping, squeaking, splashing dolphins and a few kinds of seabirds. For a transcendent minute or two, the cold ocean seemed to be boiling with creatures, the dolphins eager to sidle as close to the boat as they could. Not bad for $59 round trip (or $79 if you’re camping).

The island visitor center, which the National Park Service opened in 2009, is housed in an 1883 ranch building between the Scorpion beach and campground. The only cell phone reception is on the pier, and that is iffy. There are no public telephones, or food or water or other supplies for that matter (though potable water is available in the campground).

When I first camped on Santa Cruz in 1997, feral sheep and pigs roamed the territory, nibbling at meager patches of grass. One evening as we sat around the campfire (now forbidden), half a dozen wild horses came barreling through the campground.

The second time, in 2004, Santa Cruz was greener. A drought had eased, and the sheep and horses were gone as were most of the pigs. (The park service hired a team of hunters, some in helicopters.)

On both visits, just about every ranger and visitor I met was worried about the little island fox. Unique to the Channel Islands, the species had been classified as endangered after an NPS estimate in 2000 that fewer than 80 of the animals remained on Santa Cruz.

I had never seen one in the wild. But this time, as I dragged my gear to the campsite, I looked up.

A fox stood alongside the path, appraising me like a pickpocket chooses its victims.

Its coat was rust and gray. It was about the size of a cat, but slimmer (4 to 5 pounds) and, to quote Casey Schreiner of Modern Hiker, “ridiculously adorable.”

Was this sighting incredible luck? No. A moment later another fox meandered across the path. Then another. There are now thousands on the island, so many that their endangered status was revoked three years ago.

As I set up camp, one of them jumped onto my gear, the better to sniff for food. I had to chase it around the picnic table three times before it would leave. (You will want to use the food lockers next to the tables.)

By 9 p.m., I was in my sleeping bag. Then around midnight, the sound of a scuffle interrupted my dreams.

It was one fox chasing another across the mostly empty campground. As they raced, one of the foxes let out a kind of banshee growl — louder and lower-pitched than I expected from an animal so small. In the morning, fox poop was waiting in the middle of my picnic table.

Congratulations, island fox. In 22 years, you have made the journey from charity case to hardened criminal.

For many visitors, the island’s north coast is the big draw with one of this continent’s greatest collections of sea caves. For a sampling, I signed on for a three-hour kayak tour.

There were less than a dozen of us, mostly novices, led by guides from Channel Island Adventure Co., which also rents snorkeling equipment at the old Scorpion Ranch corral.

For hardcore kayakers, the great temptation is Painted Cave, a quarter-mile long and up to 160 feet high, on the west end of the island. For me and my fellow paddlers, the many caves northwest and southeast of Scorpion Anchorage offered plenty of excitement.

Some caves, such as Neptune’s Trident, were large enough for several of us to enter together. Shark’s Tooth was so snug and demanding that we paddled into the darkness one at a time, made a right turn, then followed another passage to daylight, leaning back to dodge the low ceiling.

The three-hour kayak tour isn’t cheap at $149 a head, but after 20 minutes, I knew I had invested well.

Hiking, on the other hand, is free. And that’s how I spent my second day on the island.

I could have walked to Smugglers Cove to the east (a 7 ½-mile out-and-back trip) or Montanon Ridge to the south (a challenging 8-mile loop with 2,200 feet of elevation gain). But I’m a sucker for coastal clifftops and set off on the Cavern Point Loop, then veered off that route to join the North Bluff Trail to the Potato Harbor Overlook (5 miles round trip with 300 feet of elevation gain, mostly hugging the clifftops on a wide trail lined with native and non-native vegetation).

Most of the time, I had the trail to myself — unless you count the bees, butterflies, and the raven I saw carrying off somebody’s bagel.

Channel Islands National Park: 805-642-1393 or nps.gov/chis.

Island Packers: Daily trips from Ventura Harbor to Santa Cruz Island. Round-trip day fares: adult (13-54), $59; senior (55), $54; child (3-12), $41; infant, free. Overnight fares higher. 805-642-1393 or islandpackers.com.

Channel Islands Adventure: Kayak tours (ages 5 and older) and snorkeling rental gear. 805-884-9283 or sbadventureco.com