Visiting Yellowstone National Park in mid-winter is a trip you're not likely to forget for the rest of your life. But how do you pull it off? Here's a primer on the logistics you'll need to tackle.

* Where Will You Stay?

Unlike summer visits to the park, in winter there are fewer lodging options in the park. A lot fewer. While summer stays offer you six destinations where you can find room with a roof -- Mammoth Hot Springs, Roosevelt, Canyon, Lake, Old Faithful, and Grant Village -- in winter there are just two in-park options, the Mammoth Hot Springs Hotel and the Old Faithful Snow Lodge. Both lodges are run by Xanterra Parks & Resorts.

If you don't feel a need to stay inside the park, there are plenty of room options in West Yellowstone, Montana, which sidles right up to the park's West Entrance, and Gardiner, Montana, just beyond the towering rock arch of the North Entrance. There also are rooms to be found in Cody, Wyoming, and Jackson, Wyoming, but, realistically, those are not good options due to the distances involved -- roughly 50 miles each way -- when it comes to traveling from either of those towns to the park.

There's one park campground open year-round, the 85-site Mammoth Campground. You also can head off into the backcountry, but you'll need a permit from the park before you do that. They are available at ranger stations and visitor centers.

* Getting Around the Park

Unlike summer, negotiating Yellowstone in winter is not exactly fancy free, as most travel along the Grand Loop is restricted to over-snow vehicles, whether that is a snowcoach or a snowmobile. Now, the road from Mammoth Hot Springs east to Roosevelt Lodge and then on east along the Northeast Entrance Road to Cooke City, Montana, is plowed through the winter. Via this route you can reach the wildlife-rich Lamar Valley for wolf watching, park at Tower and cross-country ski or snowshoe farther into the park, or reach any of the trailheads that stem off from these roads.

From Mammoth Hot Springs you also can drive a very short distance to a parking area at the Upper Terraces Area. From there you can cross-country ski along a marked trail or walk down through the terraces on a boardwalk.

If you wish to dive deeper into the park -- something that's worthwhile if you want to explore the Upper, Midway, Lower, and Monument geyser basins in winter, or are curious as to how the Lower and Upper Falls of the Yellowstone River in the Grand Canyon of the Yellowstone appear with their icy mantles -- then you'll have to pay to ride a snowmobile or snowcoach, or be a very strong cross-country skier or snowshoer.

There are a number of snowcoach options available to get you into and around the park. Yellowstone Vacations, SeeYellowstone.com, and Xanterra are just three of the possibilities available for catching a ride. These can help you get from West Yellowstone or Mammoth Hot Springs to Old Faithful, or if you're looking for a half-day or day-long adventure they will be happy to take you to various spots in the park. You can even charter an entire coach for your family or group and map out your own journey in the park.

These and other businesses also offer snowmobile rentals, though be aware that you'll have to go with a guide.

There are warming huts where you can come in out of the cold and bask in the glow of a woodstove at Madison Junction, West Thumb, Old Faithful, Fishing Bridge, Canyon, Mammoth, and Indian Creek. Some have vending machines and cold beverages.

* What Can You Do in Winter?

So, what's there to do in Yellowstone in winter? Just about everything you can do in summer.

There's wildlife to watch in the Lamar Valley. Bison are the most plentiful, but elk, coyotes and wolves also turn up with regularity. If you're staying at Mammoth Hot Springs, you can explore the terraces via the boardwalk, cross-country ski (Xanterra offers ski drop-off shuttles), or snowshoe any of the trails that head off from the northern reach of the Grand Loop Road or the Northeast Entrance Road.

If you're based at the Old Faithful Snow Lodge, you can spend endless hours on the Upper Geyser Basin boardwalk. The antics of the geysers, hot springs, and fumaroles are never boring. You can stretch your legs a bit more and venture, either on ski, snowshoe, or hiking boot, into the nearby Black Sand or Biscuit Basin areas to explore the thermal features there. You can ski or snowshoe down to Lone Star Geyser.

You can also skate on a small ice rink next to the Snow Lodge, and if you're a skate-ski convert, there's a short groomed loop at Old Faithful as well. If you're tough enough, rise early and see how far you can skate ski along the Loop Road toward Craig Pass. Overnight grooming leaves the snow surface on the road silky smooth, and if you can get out before the snowmobilers or snowcoaches get to it you'll be in Nordic heaven. Of course, you'll be skiing uphill towards the pass, which is roughly 8 miles distant. The payoffs are cruising through lodgepole forest and, if you can make it, a far-off view Shoshone Lake at Shoshone Point.

If you time things right, you might even be able to hitch a ride back to Old Faithful on one of the snowcoaches coming in from the park's South Entrance.

*What Do You Need To Pack?

Though the prospect of encountering temperatures far below zero might be daunting, if you cover the basics, and then toss in some extras if room is available, you should be OK.

The basics, of course, revolve around layering -- base layers, mid-layers, and outer layers. Synthetics and wool fabrics long have been recognized for keeping you warm and dry, though in recent years there have been strides made towards cotton fabrics that also wick moisture away from your body. Outer layers that are waterproof and breathable are best, though in winter those that are merely water-repellent might get you by as any moisture you're likely to encounter will be frozen. That said, warm snaps can happen, so if your outer shell isn't waterproof, a rain shell that is wouldn't be a bad idea to toss into your bag.

Fleece or wool hats that pull down over the ears are essential, as are good warm gloves/mittens, and insulating socks. Boots that can stand up to sub-zero temperatures and which have good treads also are a wise idea.

Not to be overlooked are sunblock and good sunglasses -- the Rocky Mountain sun shines bright, and when the landscape is covered with snow, the reflection can be pretty intense both for your skin and your eyes -- and some Chapstick or something similar.

* Helpful Websites

Yellowstone National Park: www.nps.gov/yell

Xanterra Parks & Resorts: www.yellowstonenationalparklodges.com

Yellowstone Vacations: www.yellowstonevacations.com

SeeYellowstone.com: www.seeyellowstone.com

West Yellowstone Chamber of Commerce: www.destinationyellowstone.com

Gardiner, Montana, Chamber of Commerce: www.gardinerchamber.com

Yellowstone weather: http://forecast.weather.gov/MapClick.php?zoneid=WYZ001