Hiding - camouflage a base
Just a small one, but overall I've found the hiding skill to be completely useless. I think it's the only skill where you can see a bar, but not increase that bar beyond the minimum.
Healing? Lay down a sleeping bag.
Alertness? Noise traps.
All you can do with hiding is TAKE OUT covers and things. Why not let us make a camouflage covering?