Comedy film about a honeymooning couple in a camper. She collects rocks. A later...

I believe I watched this somewhere in the early 2000s on cable TV with my parents. It looked like a movie from around the 1950s or 1960s with bright colors. It probably involved famous actors, but I don't know actors very well. Both the husband and wife were Caucasian, I think middle-class. They were traveling for their honeymoon and they had a camper, either as a vehicle or as a trailer, and the wife kept picking up (rather large) rocks from the places they stopped at as a keepsake, something which frustrated her new husband, who I think had to haul them into the camper. At a later point in the film, they're driving up a hill, and the vehicle is failing, forcing them to jettison the rocks one by one to lighten the load. I think it leads to them arguing (details I don't recall, but probably something along the lines of that he didn't understand why she was collecting rocks and she didn't know why he didn't understand the sentimental values of the rocks), with them eventually reconciling and being more in love by the end of the film.

This is The Long, Long Trailer (1954) starring Lucille Ball and Desi Arnaz.

Nicky and Tacy are going to be married. Nicky wants to save up money for a house, but Tacy dreams of starting off with their own home on wheels--a trailer.

The scene with the steep hill is here

She's been collecting rocks from each of their stops.