After a really frustrating morning googling for 70s fieldstone walls that don't look hideous, I think we're leaning towards yellow.
I cropped the right side of the room because the enormous blue recliner stands out so much it's hard to judge the other room elements. The curtains are chocolate and off-white - if the yellow doesn't clash with them, they will be a great accent for the giant stone wall.
I need to pick up a lot of light and medium yellow swatches and try them out.
The enormous blue recliner will either live in a spare room or make its debut on craigslist.