The large rock formation in the distance behind Maverick when he is playing the "sick injun" hunted by the Russian archduke, is Half Dome in Yosemite National Park, California. It's partially visible first when Maverick is attempting to ride the bicycle and again later when Maverick leaves the Native American village.
Gary Ross had been brought to rewrite the scenes involving The Magician, a character played by Linda Hunt, which were ultimately cut out of the movie after test screenings.
Jodie Foster's character's gracelessness in the film stems from the first scene she shot, when she waited for Mel Gibson to help her down from the stagecoach. Instead, he took her parasol and walked away. She tried to get down alone and flopped to the ground. Director Richard Donner liked it so much he kept the shot in the film, and staged more scenes of Foster stumbling, being dumped through windows, etc.
When Maverick, Anabelle and Cooper are talking on the ferry boat with the paddlewheel turning in the background, it can be seen that the paddlewheel is dry.
What is the signifigance of Bret uncovering the robbers face, and looking like he knows him from somewhere, and the robber looking at him the same way?
A
The robber is played by Danny Glover, who was Mel Gibson's partner in the Lethal Weapon series of films (also directed by Richard Donner). When he pulls down the mask they look at each other for a second and a musical sound bit from Lethal Weapon plays as they look at each other and shake their heads. Also when leaving the bank, Danny Glover is heard saying "I'm too old for this shit." which he says (or a variation) of in all 4 Lethal Weapon movies.