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The Friday before Thanksgiving, Chris Kain and his family watched the sun set on a beach in Oahu, Hawaii, and 12 hours later, they dazzled at the icy top of the tallest mountain in North America, Denali, as it rose in Alaska. What preceded that moment were numerous miles flown and driven across the United States to fulfill a promise Chris made when his daughter Kellisa exceeded doctors’ expectations to survive an extremely premature birth— sustaining fluid on the brain and developing cerebral palsy— about 17 and a half years ago.

The symbolism of that sunrise wasn’t lost on Chris, who at that moment was beginning the last chapter of a years-long journey to show Kellisa all 50 U.S. states before she turns 18.

“It was a huge relief because I’d been putting a lot of pressure on myself to make sure it happened,” Chris, a technical manager for a company that supports the flooring industry, told FoxNews.com.

Instead of keeping Kellisa indoors, Chris has prioritized father-daughter trips outdoors so Kellisa can live as normal a life as possible. The teen, who is reliant on a wheelchair and communicates primarily through facial expressions and basic phrases such as “yes,” has always preferred bumpy terrain to smooth pavement anyway, Chris said.

In December 2015, when FoxNews.com first spoke with Chris, he and Kellisa had hiked trails together in 47 states, and had only Iowa, Hawaii and Alaska left. But when Chris realized earlier this year that Kellisa’s adopted sister, Laurel, 7, had visited 41 states, he decided to backtrack a bit to make it so his daughters could complete the feat together.

“Kellisa wants [Laurel] by her side,” Chris said, and “Laurel has taken a very active role in wanting to help and watch out for Kellisa. She likes to help push Kellisa on these trails, and she’s real good at looking out for Kellisa’s safety.”

To catch Laurel up, Chris packed the girls’ bags plus Kellisa’s jog stroller with rugged wheels to fly to Albany, New York, from the family’s new hometown of Roseville, California, where they relocated from Florida earlier this year, when Chris received a job transfer. In three days, they traversed the Northeast by car— hitting New York, Massachusetts, Vermont and New Hampshire— and flew to Illinois before finally driving to Iowa. Cramming six states into that time span was unusual, but doing a lot in a little wasn’t atypical for the girls.

“They’re both road warriors,” Chris said.

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The following week, Chris and his wife, Lisa, flew their daughters to Oahu, where they hiked muddy trails as it drizzled, and spent five days feasting their eyes on aerial views of Honolulu and Waikiki, as well as playing on sandy beaches. From Hawaii, the Kains took an overnight flight to Anchorage, where an abundant snowfall made up for the limited trail options in the wintertime.

“Negative 14 degrees was the actual temperature— both kids loved it,” Chris said. “Laurel got out of the car and was [making] a snowball, Kellisa’s giggling … I was very impressed that they did not let the cold slow them down or stop them one bit. I had to kind of drag them back into the car because they wanted to keep playing.”

The Kains spent four days in Alaska, and now that their nationwide tour is over, Chris is already setting his sights on hiking trails outside of the U.S.

“They’ve both been to Canada, but they haven’t been to all the providences, so I’m thinking we can do that and do some trails in each of them,” Chris said.

However, in her new home state, Kellisa has all the advantages of the outdoors that many of her nationwide excursions have afforded. Lately, the Cains have been spending their time exploring local trails, sledding the Sierra Nevada Mountains, and splashing around in swimming holes and creeks in which Kellisa uses a square flotation device that allows her to independently move her hands and lightly kick her feet.

“My kids thrive in this stuff,” he said. “It doesn’t matter if it’s hot or cold or in between, or wet or dry— just that they’re doing something.”

Chris re-emphasized his goal of inspiring other parents whose children are disabled to believe in their kids and push to give them more than only what is expected.

“I see [my kids] thriving and all the kids who are sitting there at home,” he said. “That’s the bigger goal: to inspire people not necessarily to do what we do, but to do something.”