The park ranger says that the gold mine tour is meant to recreate the 49er experience. However, the national park is in New Mexico and the 1849 Gold Rush occurred in northern California.
When Bud asks Al for his shotgun (to shoot the tarantula off Al's arm), Al replies no, but that he'll give him both barrels if he doesn't get the tarantula off of him. "Both barrels" refers to the type of shotgun that has two, side by side barrels with one shot each. The type of shotgun Al has is a single barrel, pump action shotgun.
When we see Al's dream of what he is going to do with his gold we see Peggy's head as a trophy on the closet door. If you look closely as the woman puts her red teddy on Peg's face you can see Peggy close her mouth even though she is supposed to be dead.