Containers are among the most important pieces of kit in on your person, in your scout kit and of course, your cache items. Survivalists often talk about the various "c's" of survival, all seem to have a different total number of "c's", but they all include containers. We'll start with on your person.
I wear a kilt so I do not have pockets, I wear a sporran. This is my primary container which contains much of my basic kit. Even if you wear pants I encourage the use of some type of belt pouch. I like to have several. Without getting ridiculous, the more you can carry about your waist, the better.
Around my waist I have my sporran which contains several lengths of cordage, compass, small sewing kit, a very small emergency water filter with 1 yard or meter of aquarium tubing to access water in hard to reach places, a couple of Bic lighters (or thumb drills as us bushmen call them), a little vial of echinacea tincture in case of snakebite, a bandanna, a long leather cord, and any area specific items I feel I might need and can fit comfortably.
I also have a separate pouch for my double sided sharpening puck. It is about the size of a tin of tobacco and made by Gransfors Bruks. My fire kit has a dedicated pouch with a tin of pitch, fatwood, and a waterproof container for tinder and another for windproof matches. My ferro rod will go in there too if there is not a sleeve for it on my knife sheath. I do not use a flint and steel often but if you do, put that in there as well. I generally rely on my hand drill, next my ferro rod and in emergencies, a lighter. My ferro rod and lighters see VERY little use. To be honest, I barely use the pitch, fatwood, windproof matches or stored tinder either but the times I have, I was very grateful to have it.
My last pouch is an expandable bag that folds up and secured with a snap. It is used for gathering opportunistically with such items as tinder, medicinal herbs, berries, mushrooms and small game. The two other items on my belt is a tool ring for my tomahawk when I'm using it regularly and my knife or knives.
I never carry items in my pockets that I absolutely rely on, it's far too insecure in my opinion. Now if your pockets had some type of very secure closure, then most definitely put them to use. A waistcoat (vest) with a lot of pockets is a very handy piece of kit. Pants pockets when stuffed are extremely cumbersome and can severely limit your range of motion. Items in the front pockets of your pants can also put pressure on your hip flexors, causing soreness at the end of the day. The action of walking and especially squatting can push items right out.
I know a lot of people like to carry a canteen on their belt but I'm not one of them. There are some nifty designs with a nesting cup, stove and canteen but I've never had much use for one. I eat far too much than what can be cooked over the little stove and what fits in the cup. For boiling water, if I am going to take the time to start a fire, I am going to boil a proper amount, a lot more than what will fit in that little cup or canteen.
For carrying water I prefer some type of bag canteen such as a bota or wineskin. As you drink the contents, the lack of a void keeps the liquid from sloshing around. It is far quieter than a bottle and if you ensure there is absolutely no air inside it, it will be completely silent.
If you do carry a bottle, there is three real choices for long-term wilderness living; a stainless steel wide mouth canteen, a waxed leather canteen and what I use most often, whatever container you can find. It can be an old whiskey bottle or a plastic soda bottle and it is completely free. There is hardly a place on this planet where you will not find some trash, and bottles are some of the most common trash there is. Just tie a couple together and sling them over your pack or make a pouch and you are set.
Next would be the possibles bag. It's basically a man purse that you wear across your body with essential items too big for your belt that you want to have more accessible than what is in your pack. In it I most often carry a very small first-aid kit, pouches of herbs for medicinal teas and poultices, stainless cup, a couple more bandannas, several lengths of mule tape, cordage, salt, pemmican, jerky, a plant/mushroom field guide and if I am not carrying my pack, a poncho if I think it might rain. Of course, just like the sporran, adjust the contents according to the season.
Now for your pack. If I am going very light weight, I just use a blanket pack and do not bother with any kind of bag. Any more than that and my absolute favorite is an external framed pack where the frame and straps are a stand-alone item. These are often called freighter packs and are, in my opinion, essential to long-term wilderness living. They must have a fixed shelf at the base of the frame if you expect it to last.
Being able to not only carry your bags of kit, it will also double as your truck. You can haul firewood, cache tubes or trunks, butchered game, large water containers, virtually anything that you can bear the weight of. If you are going to buy one, there are only three on the market worth getting, all other will fail on you. The BullPac, the Eberlestock Mainframe and the one I would choose, the Tatonka Lastenkraxe are the absolute best on the market that I have seen.
One your frame you can use an old military A bag for your main compartment. An A bag is great, it is large, narrow enough for maneuverability and can be used as a stand-alone bag if needed. On to your frame it is easy enough to attach other bags for your gear besides the main one on either side. I like to use simple waxed canvas stuff sacks for this. Any tools can be lashed on there as well. I always like to keep provisions in it's own waxed canvas sack so I can hang it each day and keep it away from critters.
The bags on my frame consist main large bag (military A bag treated with wax) containing clothing, ammunition, small tools and possibly my bag of provisions. One of the waxed canvas stuff sacks is my snaring/trapping kit, the other is a more expansive first-aid kit. My blankets are wrapped with my ground cloth and browse bag and my tarp sits at the top of everything for quick and easy access.
My longer tools are lashed on the outside of everything and they are what I mainly use to balance the pack. Since the trapping kit is much heavier than the first-aid, the heavy tools are on the side with the first-aid. You can also position canteens to help balance but keep in mind that as you drink, the weight will go down. Sometimes my cooking pot will go in my provisions bag, or in my main bag and other times, it will get lashed onto the outside.
I generally do not carry much fishing gear unless I know I will be fishing for sure. Very little tackle will go a long way if you know how to use it. There is no need to always carry around a full tackle box and fishing rod. A hobo reel or Cuban yoyo with a stash of extra line, lures, weights, hooks, swivels and a few floats takes up very little space and weighs next to nothing. Just cache the rods and extensive tackle box at your favorite fishing spot.
Do not overdo it one the bags, it is nice for organization to have a bag for every little thing but soon you will be carrying a LOT of extra weight just in bags and containers. One of the most handy and multi-functional containers there is, is a simple sheet of cloth. You can spread it on the ground and easily gather whatever materials it can support, tie it about your waist or over your shoulder and be on your way. You can string a tumpline through it and increase it's capacity. When it is not in use, it is a scarf, sun hood, water pre-filter, awning, sash, extra pad for your pack, towel, sarong, you name it.
For your cache tubes, my favorite is PVC pipe. There is some very large diameter pipe you can get. Glue on female end cap adapters and grease the treads with Vaseline to ensure that the cap will remain waterproof and to keep them from locking up. Whatever you put in the tube, also throw in some type of dehumidifier and an extra tub of Vaseline to maintain the cache. At each and every cache point, stash a cap wrench or two. Aluminium cap wrenches are the way to go, they will not get brittle like the plastic ones might.
For long-term wilderness living in your established home territory, caching items will save you from needing to carry much on your person. Build enough permanent shelters and even your scout kit gets very light. As you build more shelter then make or acquire more containers. Once you have established homes, you can never have too much secure storage. A place for everything and everything has a place.