Occasionally, you can roll a survivor cache in a cave, but that’s pretty rare and it has only happened to me once. It’s far more likely to find an empty cave or a rat’s nest than a cache.
I was happy to see that in the latest stable version, there are now survivor houses that are heavily barricaded and laced with traps, as well as valuable loot such as guns, food, armor, ect.
I like the idea of having buried caches as well, and it shouldn’t be too hard to make it spawn as a random encounter like dead drug dealers or scientists.
I also would really be in favor of implementing a very small chance to spawn a loot-filled chest in random places such as houses, basements, or abandoned storefronts. This could make raiding ordinary locations more valuable and rewarding, especially for the particularly thorough survivor.