Goofs

The sweat marks on Katz's T-shirt during the car rental scene show three different patterns.

When Bryson and Katz arrive in the bunkhouse, a fellow hiker strikes up a conversation with Bryson. Bryson sets his pack down next to a bunk bed with only a mattress and a pillow on the top bunk, then the camera momentarily switches to the hiker. When the camera switches back to Bryson, Katz's sleeping bag has noiselessly arrived on the top bunk.

Bryson can be seen entering the laundromat with his clothes in a Mountain Hardwear Lamina 15 sleeping bag storage sack, but when he awakes in the tent after hearing bears, he is in a sleeping bag made by Big Agnes.

The postcards shown at the end from Katz are dated 2005, and in real life the hike was in the 1990s. Yet in the movie they stay at a motel with a sign that says "Founded in 1931", and Jeanine said her family has run the motel for 83 years. That would make the year 2014, nine years after Katz sent the postcards while on the trip. Also, the Daft Punk song Get Lucky came out in 2013.

The bears that were encountered at the campsite were grizzly bears. They should have been black bears, as there are no grizzlies in the eastern United States.

Bill googles the Appalachian Trail but google wasn't invented yet as a search engine.

Bryson's room has a photo of the Bill Bryson Library in Durham City and a framed certificate from the university. In reality the walk predates Bryson's time at Durham (where he was chancellor of the university) by a decade.

About halfway through, when Bryson lies down on the lower bunk bed in the bunkhouse and looks up at Katz, he sees a large gap in the bed construction above him, with the mattress poking through. The implication is that the mattress is about to come through, with Katz on it. When Katz does fall through, there is the sound of wood breaking, although no wood is shown falling, just the mattress and Katz. So the gap is irrelevant. Also, the mattress Katz is lying on has two by fours on either side of it, which would easily support his weight, unless they were rotten. Both the gap and rotted timbers would be actionable and make the owner liable for personal injury. (Katz would be fine, but 70-year old Bryson would be hit by over 200 lbs. falling on him, not to mention the invisible wood).

When Bryson and Katz arrive on foot at "the bunkhouse" the day after the snowstorm, the camp is covered in snow, but the surrounding trees and foliage are totally devoid of snow.

Bryson's hair length doesn't change through the entire movie, and Katz's beard remains the same throughout.

After three months, the hiker's backpacks still look new, and neither of them appears to have lost any weight.

Bryson and Katz are at a New Hampshire airport in March, but the trees are in full leaf, indicating the scene was shot in the summer.

Bill and Stephen's backpacks would be heavy. Yet there are several scenes where they seem to be effortless to lift, or move.

The Greyhound bus has an icon for Internet on Board.

(at around 1h 34 mins) A crew member in a yellow vest is seen standing in front of a vehicle with its headlights on, holding back traffic for filming. In addition, a couple of people are standing between parked cars watching the filming.

The map shown in the shelter is very inaccurate. It does not show the Appalachian Trail passing through West Virginia, New Jersey, or Connecticut. It also reverses New Hampshire and Vermont.

They are seen looking at a map that puts them in Northern Virginia. Then, after refusing the rental car and hiking more, they are at McAfee Knob in Southern Virginia. They also pass the power house at Fontana dam in that same hiking sequence that is seen earlier in North Carolina (on top of the dam).

They're wearing way too much cotton.