Usually a couple waits until retirement to take that year-long dream vacation. Not Elizabeth and Cole Donelson.
The Kansas City, Mo., 25-year-olds are in the middle of a journey that will take them to all 59 national parks. They started on Aug. 18 at Mesa Verde National Park in Colorado and plan to finish next Aug. 25 -- the centennial of the National Park Service -- at the Jefferson National Expansion Memorial, better known as St. Louis' Gateway Arch.
While it's not specifically a national park, "That's our home park, the closest, so that's our big finish," Elizabeth said.
The pair is not doing this with luxury in mind. They're sleeping on air mattresses, in their car, anywhere in the parks they can remain close with nature.
"There are points where we wish we had an RV or could splurge for a hotel," Cole said. "So being in a tent means you're exposed for a long time. In the Great Smoky Mountains, it rained four of the five days we were there."
Sunday marks the end of their South Florida leg.
They started by camping at Dry Tortugas National Park Nov. 17, 18 and 19. Then they hit Everglades National Park, staying until Nov. 22. Sunday, they finish up their time in Biscayne National Park, then head to Virgin Islands National Park.
"In the Tortugas, the only way to do the park is to camp," Cole said. "You could have a good experience during the day but really being there when the ferry leaves and almost having the beach to yourself and watching the sunset was phenomenal. We really wanted to get out to Loggerhead Key, but it was so windy, they advised against kayaking out there."
Cole said the most enjoyable part of each park visit was its respective individualness.
That's part of being out in the remote wilderness, "the places you know that hardly anyone has ever been to, getting into these places and getting off the beaten trail. One example is the Everglades. We have an inflatable kayak. We took it around Nine Mile Pond. The only things we could see were the birds and the mangroves.
"It's doing things like that that get you deeper into the park, beyond the crowds, which is what we strive for."
That goes to the name of their journey, Switchback Kids.
"It was kind of a name that my wife thought up," Cole said. "Really, I guess we thought it was catchy and fun. The deeper meaning is switch back, we're going through all these parks and compared to other national park travelers, we're kind of young. When you go up a mountain, you can't go straight up, you have to double back. It gives you a wider view of the beauty."
"We were both in our careers. Sometimes it's not about the money. You have to step back and see what makes you happy," he said.
They attended the University of Missouri, meeting during an ultimate Frisbee game. Elizabeth got a degree in education and went on to become a sixth-grade teacher. Cole majored in journalism and business and worked at a health-care IT company.
Those careers are likely long in their past. As for the present, they have parks to see. It's both exhilarating and a challenge.
"We have an air sleeping pad that has been leaking for the past three weeks. We have two of them, one for each of us," Cole said. "It's just been driving us crazy, when you have to wake up five times a night to blow the air mattress back up. But we had lots of preparation for the trip."
"Cole is definitely better about the whole sleeping outside, sleeping in the car, not showering," Elizabeth said. "I think I miss some of the homey things, little things like decorating for the holidays. But I'm surprised; those things like sleeping out of a car have been less of a challenge as we go along."
So what was the reaction from the parents when told about the trip?
"At first they didn't think we were going to do it," Elizabeth said. "Then they were supportive and a little jealous, both our sets of parents. Cole's parents are joining us quite a bit. They joined us in Shenandoah and will be joining us in the Virgin Islands."
Cole said the trip is not that expensive, considering it's a year.
"It's all self-funding. We did a bunch of saving before the trip and we calculated it would take $20,000, $25,000 for the two of us. We're camping everywhere. We get pretty good mileage in our Ford Escape."
So how do they top this?
"I don't know," Elizabeth said. "We have a list of things we want to see. As we do the parks, there are other things we want to do near them. There are 409 parks, national historic sites -- we want to keep aiming, maybe not hit all of them but keep our travel focus on all of them."
To follow their journey, go to http://switchbackkids.com
Properties under the National Park Service
Following are all "units" under the National Park Service:
National parks, 59.
National memorials, 30.
National monuments, 80.
National battlefields, 11.
National battlefield parks, four.
National battlefield site, one.
National military parks, nine.
National historical parks, 50
National historic sites, 78.
International historic sites, one.
National lakeshores, four.
National parkways, four.
National preserves, 19.
National reserves, two.
National recreation areas, 18.
National rivers, five.
National wild and scenic rivers and riverways, 10.
National scenic trails, three.
National seashores, 10.
Other designations, 11