(Fred Ernst/Reuters)

Have you tried to book a room for the solar eclipse, only to find that reservations are running $600 per night? Maybe all of the hotels in the city are already completely full. Perhaps you’re just going to wing it — throw a sleeping bag in the trunk and hit the road the night before. That’s exciting! But it’s good to know what you’re getting into before you get in the car.

Many small towns across what is often billed as “flyover country” have been preparing for the influx for years. For most of these typically-unvisited parts of the country, it will be the largest crowd of people they will ever experience.

Diane Kelly gives us just one example of the looming madness for Fivethirtyeight.com:

The 200-person town of Glendo, Wyoming, about 200 miles north of Denver, expects to host at least 20,000 people at its viewing area on a grass airstrip — and at least an additional 30,000 are expected at the neighboring state park. “We’ve actually been planning for this for three years,” Town Clerk Brenda Hagen said. “It’s a once-in-a-lifetime event for us.”

Kelly also points out an obvious fact that perhaps many eclipse watchers will have overlooked — small towns may not have enough bathroom facilities for thousands of visitors, and “no one likes an overflowing toilet.” I, for one, do not want to be in charge of the bathroom facilities in any of these small towns.

Yours truly will be staying in Bryson City, N.C., a little town in far-western North Carolina near Great Smoky Mountains National Park. The population on an average day is just 1,400 people. On Aug. 21, it could be more like 14,000. (I’m told the town is making T-shirts to celebrate the event. I can’t wait to get my hands on one of those.)

I booked a house in advance, but if I decided to drive down from Washington, D.C., on Sunday — or even early Monday morning on the 21st — I probably wouldn’t reach the path of totality in time. That’s not because I’m a terrible driver with no sense of direction (which may or may not be accurate) but because millions of people live within a reasonable driving distance of the path.

The total solar eclipse in August 2017 will travel across the United States from Oregon to South Carolina. But if the moon rises in the east and sets in the west, why does the eclipse shadow travel from west to east? Dear Science is on the case. (Daron Taylor,Jorge Ribas/The Washington Post)

The website Greatamericaneclipse.com pretty much sums it up when they say, “the accessibility of the August 21 total solar eclipse is simultaneously a great benefit and a problem.”

The benefit is that for so many millions of Americans, nature’s grandest sight — a total eclipse of the Sun — can be seen by packing a tent and sleeping bags and taking a short road trip from home. To see the stunning spectacle of totality, you have to be within the 60 to 70 mile wide path There is plenty of room inside the path, provided people distribute themselves well.

The problem is that these millions of Americans will produce predictable traffic congestion. Imagine 20 Woodstock festivals occurring simultaneously across the nation. Large numbers of visitors will overwhelm lodging and other resources in the path of totality. There is a real danger during the two minutes of totality that traffic still on the road will pull over at unsafe locations with distracted drivers behind them.

Average drive time to the Aug. 21 total solar eclipse. This doesn’t include an estimate of traffic on the day-of. (greatamericaneclipse.com)

Great American Eclipse offers an extremely rough estimate of how many people will be traveling to see the eclipse — between 1.8 million and 7.4 million. If a couple million people pile onto the roads on the evening of Aug. 20 or the morning of Aug. 21, traffic could be bonkers. Michael Zeiler, one of the minds behind the Great American Eclipse website, used average travel times to create the map above.

Traffic will probably be the worst east of the Mississippi, although areas that have low road density will also be subject to congestion. Bottlenecks seem likely in the Appalachian Mountains — I suspect lots of people will want to get into nature to view this natural phenomenon, but the road system isn’t necessarily robust enough to support the crowd.

Our advice is to treat this like a holiday weekend on the East Coast: Leave early and plan for delays.