Goofs

In the beginning of the film, Jim Fallon appears in the window opening the divided curtain with both hands. Then the curtain on his right-hand side remains open while he holds the other part with his left hand. In the following shot from inside, the part on his right-hand side is closed.

In the saloon, Daisy dances around and returns to the stage with the help of two men who suspend her. Then we see a fat man standing on the stage corner, in front of a drink glass, clapping her. In the next shot he is drinking.

Judging by the filming locations, the trees are coast redwoods (sequoia semerivirons). Giant sequoia are referenced in the writings on this film. Giant sequoia (sequoiadendron giganteum) are a different species located far away from these coastal filming locations in the Sierra Nevada Mountains.

Once Kirk Douglas has the brake tightened down enough, that the steel wheels of the caboose are sliding on the rails. He could have stopped turning the brake wheel they won't get any tighter. They'll just continue to slide.

"Yukon" Burns is buried in a Quaker cemetery, which contains many graves built close to the trunks of big trees. How these graves could be dug to a reasonable depth with the huge roots they must have had is not explained.

Walter 'Yukon' Burns has come from the Yukon gold rush, supposedly in Alaska. Although the gold fields of the Yukon Gold Rush of 1897 were predominately in Canada, the Yukon Territory is (and was) completely landlocked, accessibly only by traveling through Alaska on routes such as the Chilkoot Trail, the White Pass Trail, or the Klondike River. It is appropriate to regard 'Yukon' Burns as coming from Alaska.

At least twice characters quote the "verse" God helps them who helps themselves.