Imagine traveling thousands of miles to get to Alaska, then 300 more to reach the tiny community of McCarthy, deep in the heart of our country's largest national park, Wrangell-St. Elias. Then imagine loading yourself into a tiny bush plane and landing beside a lake full of icebergs at the toe of a giant glacier. Two rafts sit by the edge of the lake, surrounded by wildflowers, alongside a campsite where lunch is being served. The whole scene is dwarfed by the surrounding scenery of ice, rock and tundra. The plane flies away and you and your guides are left to enjoy 15 days in this stunning and remote wilderness.

After paddling amongst the icebergs, you head for the sound of rushing water, where the Nizina River heads south out of the lake. For the next two weeks you will travel the Nizina, Chitina and Copper rivers all the way from the interior of the park to the Copper River Delta on the gulf of Alaska. Days of floating are interspersed with hiking alongside the river and into the surrounding mountains. Three-course meals are cooked in our portable river-side kitchen, and campfires are a nightly affair where you can enjoy dessert and a glass of wine while watching the river flow past through the endless summer twilight. The trip ends in the quaint fishing village of Cordova, where we will arrange a ferry or flight back to Anchorage.-- Copper Oar Rafting

Paints an incredible picture, doesn't it?

Paddling a river or lake in a national park setting is truly a wonderful, memorable experience. A decade before the New River in West Virginia became a unit of the National Park System, I cut my white-water teeth -- figuratively, that is -- on its rapids. I was in the right place -- college -- at the right time to be hired as a guide on that great river.

Since those days, which also provided me an opportunity to float the Gauley River, another eastern great, I've been fortunate to paddle in Yellowstone, Glacier, Dinosaur, Acadia, and Cape Cod National Seashore, just to name some of my watery excursions in the park system.

Veteran paddlers have their special spots in the park system; I love canoeing in Yellowstone, and the scenery on the Yampa River in Dinosaur National Monument is gorgeous. It's easy to tell one of the favorites of Greg Breining, who earlier this week wrote about padding along the St. Croix National Scenic Riverway.

But if you're new to paddling, or haven't had many opportuities to sample the various opportunities, how do you choose which river to float?  After all, the experiences are highly varied and diverse: Are you looking for white-water thrills or mellowness surrounded by great scenery? Would you rather paddle a canoe or sea kayak than ride in a raft? Do you want to explore a lake or head downstream on a river? Do you have a half-day, or half a month? Is your idea of a float trip based on doing some fishing, or bucking some rapids? What are the ages of those in your group?

Across the park system, you likely can find something that meets your desires. Just remember your limits. While paddling either Shoshone Lake or Yellowstone Lake in Yellowstone can be idyllic, when the weather turns and winds rise it can get pretty dangerous, so you best have the skills or a good guide to help you explore those lakes.

Though there are some rapids to test your skills on the Yampa River, there is also lots of time to relax under the sun while drifting downstream. Cataract Canyon in Canyonlands can offer tremendous white-water...as well as opportunities to explore side canyons. Putting in on one of the great rivers in Wrangell-St. Elias sends you deep into the Alaska wilderness, truly a once-in-a-lifetime experience.

There are pluses to all those options, which can complicate the decision-making process. So many options, so many experiences, so many decisions. Fortunately, sometimes they sort themselves out quite quickly.

“In terms of people choosing a trip, a lot of it unfortunately depends on people’s budget of both time and money," says Gaia Marrs at Copper Oar, a river-running company that specializes in trips at Wrangell-St. Elias.

Back in the Lower 48, Karen Johnson at Holiday River Expeditions, which offers trips on the Green, Yampa, and Colorado rivers through Dinosaur and Canyonlands National Park, says that same answer often arises.

"The first thing I do is find out how long they want to be out. It’s kind of funny, I think they end up (on a particular trip) because it’s the only thing that works. A lot of times they don’t call and say, 'I want a trip in Dinisoaur National Monument,'"  said Ms. Johnson, whose company has been running rapids in the West since 1966.

If your schedule and budget are no impediments to when and where you travel, then your next most likely next question to answer revolves around the experience you're seeking.

"River trips can range from less than half-a-day to nearly 3 weeks in length," points out Steve Markle at O.A.R.S., which since 1969 has been offering a wide variety of trips in the West, many in national park settings. "During which season are you available to travel? Weather and water levels and even hiking and fishing options can vary from season to season. What type of scenery appeals to you? Do you prefer desert canyons, alpine forests or rolling grasslands? Maybe dramatic peaks and calving  glaciers?"

Also to be considered, he notes, is whether you want to actively participate in paddling downstream, or simply sit back and enjoy the ride.

"Boat options range from oar rafts or dories where your guide rows from the middle to paddle boats and inflatable kayaks where you participate in propelling your boat down river," said Mr. Markle.

Sorting through these questions can be intimidating...or great fun. Of course, they also could potentially lead to disappointment because there are so many great options out there and you might only have time and money for one trip in a year.

There are various ways to work through these options. You can visit websites, such as Paddling.net, which has trip reports from folks who have been out paddling, or you can head to the National Park Service's website and search by activity to find parks with paddling options. To find an outfitter that offers river trips, check the individual park pages for a list of permitted businesses. Those are usually linked to from the park's "Things To Do" pages.

Then, of course, are the outfitters' websites, which usually offer a great deal of information. If you don't have a particular outfitters' name in mind, simply search the 'net for topics such as "national park paddling outfitters" or simply "paddling outfitters." Once you find these sites, you can sift through the various trips each outfitter offers.

"Then you can start to put something together that matches what your family is looking for," said Hillary Hutchison, who handles public relations for the Glacier Raft Co. that offers floats on sections of the Flathead River that help define Glacier's western and southern boundaries. "If you have a couple of teenagers who are going to be into whitewater, we can put them into an inflatable kayak where it will give them a little bit more thrill” while the rest of the family stays somewhat drier in a raft.

Groups that have different goals in mind, paddling-wise, can be accommodated by some outfitters.

“We can do a half-day fly fishing trip and a half-day white water trip and they’re in the same area and we can wind up at the end of the day in the same spot," said Ms. Hutchison.

Of course, it's always good to quiz outfitters over the phone. What's their safety record, how long have they been in business, even questions surrounding their menu should be considered. You also have to be honest with yourself in terms of what you're looking for and how much of a challenge you can take on.

"Everyone needs to realize these are not Disney Rides on a track, so go with experience," said Darwon Stoneman, owner of Glacier Raft, which has been in business since 1976. "We gear most of our trips to families with the ability for the thrill seekers to add a little challenge and excitement."

Don't worry about going overboard "roughing it" on the river. Today's outfitted paddling trips can be a lot more comfortable than you might think.

"From the custom-made super sleeper pads that people sleep on to the common
area the guides set up complete with a library, appetizer table, chairs and the portable bathrooms set up with a hand wash system, creature comforts have come a long way," notes Ms. Johnson at Holiday River Expeditions.

Of course, you also can do it yourself if you've got the skills and the equipment. Arranging your own trip takes a little time and effort, but can be greatly rewarding. Simply pick the park you want to paddle in, visit its "boating" page on the park website, and see what you need to do to obtain a permit.

Once the permit is in hand and the park requirements are understood (Do you need to pack out bodily wastes, are paddling helmets required?) the hard work begins. That entails pulling all your gear together, devising a menu, buying and packing all the food and beverages, and getting to the put-in on time.

But once you've done run your own trips two or three times, the work really isn't that overwhelming, and the joy of paddling in the parks will keep you coming back.

Tomorrow we'll take a look at some of the many paddling opportunities across the National Park System.