Word for a hideout that's not for hiding

Question

I'm writing a book in which the main character has a "hideout" in a small cave. Except, it's not for hiding. It's a place to dump tools and equipment that you'd need for a cave expedition. It has some decorative plants that can survive in there -- it's not entirely dark; there's a hole in the ceiling. There's an old table and a chair, so you can sit down and eat. The main character also uses it as a research base for the cave he is exploring, so it has some scientific tools inside. You could probably sleep in it, but it'd be very uncomfortable.

The closest thing I can think of, is this scene from Princess of Nausicaä:

My place has less plants, more tools, is smaller, and is in a cave instead. Nausicaä simply calls this place "my secret room" (秘密の部屋), but unfortunately my place is neither secret nor a room.

What's a possible word for this?

Terms that don't quite fit:

• A base is the closest thing I can think of, but the place lies in walking distance from the character's house. Bit weird to call this a base imo, unless the main character is 12 (he's 20). "A base" also sounds like it should be kinda sophisticated.
• A room implies something more... room-y. It's a cave, not a room. The term "his room" also runs in danger of confusing it with his room in his house.
• A shelter or hideout is more for hiding or, well, sheltering. He's doing neither.
• Den, nest etc. fit the general feel I'm going for pretty well, funnily enough, but my character is not an animal.
• Lair: My character is not an elder lich

Here are two solutions that would work but are not ideal:

• <adj.> room: I'm sure I can find something here, if I fine-tune the adjective
• giving it an obviously idiomatic, or proper name: "his hole", "The Place"

Example sentence: "Damn, I forgot my notebook in <the place>. Gonna head back."

Answer 1

Cache. Or perhaps depot but I feel like cache is a bitter fit overall.

"Storage cave" is a bit unusual but "storage shed" is common. I suppose if I had a cave I stored things in, it would be my storage cave, though. I might somewhat tongue-in-cheek refer to it as my warehouse. ("Be right back, need to grab something from the warehouse.")

Although for an idiomatic or rather silly name, I could see calling it something like "Home Depot" (or some other popular supply store). At my last job we had a supply cabinet we called "Best Buy". Does anyone have a spare USB extension cord? Go check Best Buy, I think I saw one in there.

Answer 2

Since your character starts his explorations of the cave system from there, maybe base camp would suit. I was thinking it was analogous to the base camp of mountaineers and polar explorers.