As to WHERE to stash your cache, i suggest you have several locations picked out. The FIRST caches you will want to make should be no more than half a day stroll from your home. This will be your FIRST resupply upon leaving, so you should have the things necessary for you to make it to any other cache location you have. Things like ammo for ALL your firearms should be in these locations. Not so much ammo as to weigh you down, but enough to defend yourself against a fair sized band of marauders, a few 'nutrition bars' for EACH individual, a first aid kit containing: antiseptic, antibiotic, water purification, bandages (and i do not mean band-aids), a collapsible splint if you FIND one.
In secondary caches, i would put things like tarps (shelter), bedding (a GOOD subzero sleeping bag), MORE ammo, MORE nutritious foodstuffs, and a more extensive med kit. The secondary caches should be set up between your home and your final bug out location. The supplies in them should last you to the next one on your way to the bugout.
The bugout location should have a cache with the tools you will need to make your NEW home livable.
As Joe said, putting your cache in NONbiodegradable containers is not a bad idea. But they MUST be weatherproof also. Personally, mine are individually wrapped in plastic bags THEN placed in watertight containers...of course, SOME of my caches are sunk in streams and lakes...
have a old car /pickup truck that runs on points- EMP,s WILL take out your computer in your car/truck. so ALWAYS have an old one around. Something like 1975 backwards- Must run on points only- have an extea coil bagged and tagged and stored in a lead container. JUST INCASE the EMP,s take out your coil to. I dont think that will happen but please check it out and when you do come back here and tell us what you did. I have what i just stated. Also if you have a old deisel tractor it will run on stove oil/kerosene/ vegatable oil and the like. biodiesel they call it. an old tractor is almost as good a 4x4 only much slower and will haul a trailer. .. Look at the old Russia and how alot of them still get around. If you have a deisel and you run out of fuel -only----if YOU have varsol fill it up but add 15%volume motor oil - you can drive it- smakes like crazy but you will get there. Straight varsol will take out the dbearings thats why you add the oil. if you run out of motor oil - use rearend oil. it will work. Never get rid of your old oil. you can use it for a stve fire and get heat when your wood it wet . OR get paper and toilet paper and filters and run your oil thru that. OIL doesnt not break down- it gets dirty- thats why you change it. So for me i would target garages when things go down..ABOVE ALL ---SHUT UP about what you do and make sure no-one knows what and why you do things....Remember loose lips sink ships..........not trying to be mean in what i say- just trying to save a life------Blessings -Ed