Ground cacheing.

A great short term ground cache can be made of an 18 wheeler inner tube and a couple of hose clamps and it holds A LOT of stuff,and you can cram it in your backpack and haul it away when you're done.you can make several for almost nothing and put them at strategic locations for later use,although not designed for it,mine lasted 5 years.

Here's the how-to:
Go to any garage that works on large trucks and ask if you can have some old truck inner tubes.

Cut the inner tube in half,removeing the valve stem.

roll up one end and put a hose clamp on it,slop it full of rubber cement and let dry.

Put in your goodies [and a dessicant pack!]and repeat.

Here's what was in mine,just as a suggestion:
An SKS carbine,oiled,not greased and slid into an old sock.
A K-Bar.[not stored in the sheath,wrapped in a cloth.]
150 rounds of Ammo.
2 BDU sets.
2 pr socks.
2 t-shirts.
2 pr underwear.
4 MRE pouches.
1 small med kit.
1 cheapo water purifier.

But basically anything that will fit can be crammed in there,the rubber stretches so it can be packed tight,just leave enough room to roll the end and put your clamp on.