I believe it was sometime during the 70/80s I would have seen a movie/TV show with the following elements. I could be combining several shows/movies together. I am unsure.
1) There is a motor-home crossing a desert. I am under the impression it is a post apocalyptic desert and the occupants are attempting to survive.
2) These people - possibly the occupants of the motor-home find refuge among others. Then the group gets a attacked/or captured by some sort of beast like creature. They have to escape, their escape must go around a pit of lava/fire. They only have one set of glasses to protect their eyes and guy wears them and leads them around this pit and lava/fire to safety.
3) There is a cave. In a cave is a black shiny rock. Someone goes into the cave and gets all weird and shaky. I am under the impression the rock is from an alien world.
4) There is a guy traveling he comes to an edge of a swamp a great nasty beast arises and they make small talk and the beast - made of garbage (?) does not kill him.
Could be I am combining some movies/tv together. I was a child when I saw these shows, information gets rewritten and fuzzy when one ages.