Jarred Evans has explored every inch of the Air Force barracks where he has lived under federal quarantine for the past eight days. He has measured out its exact length: 0.45 miles. He has run through every stairwell, hallway and parking lot row hundreds of times, trying to keep in shape and stay sane.

“It’s all in the mind. You have to stay mentally strong,” said Evans, 27, who was playing American football professionally in Wuhan, China, before he became one of 195 evacuees now living at the March Air Reserve Base in Riverside County, Calif.

Twice a day, the evacuees have their temperatures checked by medical staff in protective gear. They are forbidden to stray from a small patch of land on a base filled with armed military personnel. So they have found creative ways of filling the days.

“When people hear quarantine, they think of the zombie apocalypse, movies like ‘World War Z,’ ” said Matthew McCoy, 55, another evacuee. “But the reality is it’s what you make of it.”

Amid the country’s first federal quarantine in more than 50 years, complete strangers have become confidants. Many in the March Air Reserve group have started offering classes in their areas of expertise: boxing classes led by a boxing enthusiast. A seminar on preparing income taxes by an accountant. Zumba classes from a workout fiend. McCoy, who worked as a theme park designer in China, has experience drawing murals. So he’s planning a class for children on how to doodle with chalk using the barracks’s sidewalk as their canvas.

The 195 evacuees at the March Air Reserve Base were on the first chartered plane from Wuhan, landing in the United States on Jan. 29 and are the furthest along in the government’s mandated 14-day confinement.

From the base’s barracks, they have closely followed the chaos they narrowly escaped in Wuhan. The infection count in China has risen to 31,000 cases — including more than 4,800 considered critical and about 70 new deaths on Thursday alone, bringing the death toll to at least 637. Among the newly deceased was Chinese doctor Li Wenliang, who sounded the alarm about the disease in December and was detained, becoming a symbol of the Chinese government’s failings in the early days of the outbreak.

On Wednesday, two planes chartered by the State Department delivered 178 people to Travis Air Force Base outside Sacramento and 170 to the Marine Corps Air Station Miramar in San Diego. Two more planes carrying about 300 passengers departed Wuhan on Thursday and were scheduled to arrive at unspecified locations in the United States on Friday morning, State Department officials said.

That first day of their arrival, evacuees report, is often the most jarring. Just hours before they landed, many evacuees say, they were fearing for their lives in Wuhan and fighting desperately for a ticket out of the chaos. They recount navigating through apocalyptic scenes of a city of 11 million in full lockdown, with police checkpoints every few kilometers.

Ilona and Claude Blouin — who were visiting their son Craig, a math teacher in Wuhan — spent a week trapped in their son’s apartment before securing a spot on one of the flights that arrived Wednesday.

They flew on a cargo plane with no windows, red wristbands assigned to each passenger noting their body temperature upon boarding, and a flight crew dressed in full hazmat suits.

Half a day later, they emerged in sunny Northern California, greeted by friendly military personnel and escorted to rooms in a four-story hotel on Travis Air Force Base rimmed by a perimeter fence.

They were given masks and instructions to stay six feet away from one another at all times and to eat their meals in their rooms to reduce risk of contagion.

The children in the group — about 20 in all — were told not to intermingle and to play only with siblings.

Despite the restrictions, the overwhelming feeling was relief and gratitude.

“Everybody was so glad to come home,” said Ilona Blouin, 59, a bank manager.

That first night, the couple went to bed early suffering from jet lag and a missed dinner. When they woke up around midnight, they found pizza left for them on the tables near the elevator. Claude Blouin, 63, an engineer for a car component company, was so excited he grabbed a whole box.

“Before all this happened, we didn’t even touch pizza,” Ilona Blouin said. “Too many carbs.”

Food has also become a focus for Esther Tebeka and her 15-year-old daughter.

As observant Orthodox Jews, keeping kosher on the March Air Reserve Base has been a logistical nightmare.

With no kosher food available on board the cargo plane Tebeka and her daughter didn’t eat for 40 hours and couldn’t find anything to eat at the base when they landed last week.

“We cannot really blame the Air Force Base or the staff,” Tebeka said. Given the circumstances, they were grateful to be there. “The U.S. government has been very generous . . . One of the reasons we love the U.S. and we love our country is for this. They rescued us from Wuhan.”

Tebeka’s husband drove six hours from their home in Palo Alto to bring kosher meals for them. “The phone in my room rang,” recalled Tebeka. “I was told, ‘Your husband dropped off the food; he is in the visitors center.’ I said, ‘Okay, I’m coming.’ ”

Tebeka left the barracks, trying to find the visitors center and soon found herself surrounded by cars and military personnel carrying guns.

“They said, ‘Don’t you know this is an Air Force base? You’re not allowed to walk around’ . . . They said, ‘Go back,’ ” Tebeka said. Eventually, staff delivered the food directly to their rooms.

A nonprofit called Project Strong One heard of their plight and went on an emergency shopping trip with Tebeka’s rabbi to bring her an electric skillet and kosher staples.

But perhaps the most lavishly praised item among the people stuck at March Air Reserve Base is a little coffee maker the nonprofit procured.

“To be honest, the coffee at the barracks is pretty bad,” said McCoy, the theme park designer.

When volunteers tried to bring in better coffee, officials from the Centers for Disease Control and Prevention intervened, saying any products had to be individually wrapped and dispensed to prevent contagion. Communal coffee was definitely out of the question.

So the volunteers struck on the idea of a Keurig K-Cup coffee dispenser.

“It tastes like the fanciest gourmet stuff you’ve ever had,” McCoy said.

Many evacuees said the thing that has helped them most is their conversations with one another.

“At first, we were just telling our escape stories — how did you manage to get out, that kind of thing. But that got old pretty fast,” said Evans, the football player. “Then you start talking about who you are, where you come from, what you brought you to Wuhan halfway across the world. Pretty heavy stuff.”

The one thing Evans hasn’t told anyone in the group, however, is the guilt he feels.

“I know I’m one of the lucky ones. I have Chinese friends and teammates back in Wuhan who I know aren’t going to be able to get out, no matter how bad the situation gets,” he said. “These are people I would invite to my wedding, that I played with and sacrificed for. Deep down in my heart, yeah, I feel like I just left them behind.”

McCoy, who runs and trains with Evans every day at 5 a.m., said he deliberately keeps himself as busy as possible to keep positive thoughts foremost in his mind.

“That’s the thing I think we’ve learned most from all this. In a situation like this, it could easily go the other way — to be driven by fear and worry. But as a group, we’ve decided to stay positive and take care of each other,” he said.

Recently, as they’ve counted down their days to freedom, the group has talked about creating a video with all the lessons they’ve learned to give to others just now landing to start their time in quarantine.

“We want to tell them to stick together and be there for each other,” McCoy said, “because that’s the only way you’re going to get through it.”

Alice Crites and Carol Morello contributed to this report.