I would like the input of others here. But not on grammar or spelling. I'm not publishing a book here
Keep the calibers to a minimum. I would say .40 or 9mm because they are so dang plentiful.
As far as rifles, keep a rifle chambered in 5.56, or 7.62x39
I say 5.56 because the 5.56 NATO round has higher case pressures than the .223, and you can use the .223 in a rifle chambered for 5.56 but not the other way around.
The handgun is for last resort, the rifle in 5.56 or 7.62x39 for two legged critters.
In addition, I would say have a bolt action rifle in a commonly found round, such as the 7.62x51 NATO or the .30-06 for larger game, or long range shots.
I would also keep a 12 GA shotgun for hunting birds, and a .22 for other small animals.
Your main food source is not going to be deer. Some people think so, but unless you live in a very rural area, there will not be enough deer to feed everyone, and will be very quickly hunted out.
The reality is you may be eating Rover. Not to mention, in the summer, if you kill a large animal such as a deer, you are not going to be able to eat all of the meat before it rots. Therefore, teamwork will probably be the best way to go.
No way you should be trying to go on your own here. You should be teaming up with your community.
I figure the best way would be to breed cats and rabbits for food. They both breed like crazy, can eat very easily found foods, and don't need huge pieces of land, or large amounts of water to thrive.
Now, for the long haul, maybe a blackpowder flintlock may be the best for hunting. You can make your own black powder, you can cast your own bullets, you can find flint and steel, and you can mine the lead, and in that sort of situation, you can even use car batteries for a lead source.
I do not recomend doing this normally, it is dangerous.
If the hospital ends up in ruins, go dismantle the x-ray room, you'll never need any more lead.
Hmm, what else, Oh! If you live where water is scarce, collect rainwater, and dew. All you need to do is boil the water, and you're good.
And always keep extra. Soap is easily made from various things, one of the main ingredients being animal fat, which you will have from your meat source. Save all the fat.
Soap will be important, remember that disease was a huge problem before we figured out we needed to keep clean, and sponge baths will be the way to go, not filling up the dang tub!
you can easily heat the water in the summer, by just leaving the water you need heated in a steel or glass container in the sun all day.
Learn to use flint and steel to make a fire. Char cloth will be needed, but it's pretty easy to make once you have a fire going. All you would need is a fire, an altoids tin or something like that, and cotton cloth.
Put a hole in the top of the can, put the cloth in the can, and put the can in the fire, the can will smoke, and when it's done, you have char cloth.
Eh, It's a very good idea to make planter boxes, you can make them wherever you are, using railroad ties or the like, and you can put whatever soil you need in them. This way, you can grow a wider variety of food, since many need slightly different soil to grow. It's also easier to keep weeds out of them.
Now for shelter, if you are settling down in an area for a while, try to make your house with adobe. It's easy enough to make, and it is a very good insulator. Keeps cooler in the summer, and warmer in the winter.
Wood doesn't insulate well. Always keep a fire vent, and a place you can make a fire. If you can, making shelters out of animal pelts will be a good mobile way to keep warm in the winter. The indians knew what they were doing.
In all honesty, don't expect to have any creature comforts. Some expect to have access to gasoline for their generators. Not probable, more probable is that the entire [auto-filtered] scenario will be caused by $20 a gallon gas prices.
Leave all electronic devices back, unless you have some nice batteries.
The rabbits I mentioned earlier, can also make for some great cold weather clothing, but you should raise something like cotton tails instead of jacks, and either way, you should use the summer pelts for summer garb, and the winter pelts for winter garb. The winter pelts will have thicker hollow hairs, and will therefore keep you warmer. Many should be turned into rawhide, will come in very handy for making your clothing. By the way, cook them well, parasites suck.
Talk to some trappers to figure out how to tan a hide. I would say talk to taxidermists, but unless they do it the old way, some like to use chemicals.
Keep some good quality boots on hand. The military uses some really good boots, so take a look at those. They aren't that expensive really, and really durable. But the biggest thing is that they're waterproof.
Wool clothes are going to be the best to have around in the cold. And long sleeve shirts year round. Look at Iraq, and all of those other middle eastern countries. They don't cover themselves like that because it's comfortable.
It keeps the sun off of them. Learn to wrap your face against the sun.
Don't think you are going to rely on sunscreen.
Excercise, get out into the country and hike. Trust me, you don't want to have your first heart attack because you hiked further than you were used to. Especially in a [auto-filtered] scenario.
Remember, your initial stockpiling is only going to last you so long. If the scenario lasts longer than your stockpile, then you better learn to adapt.
Now, if you are thinking about preparing for a nuclear attack, well, that's an essay for a different time.
Then you have to think about a shelter from the initial blast, as well as the radiation, and the fallout. You get into protection factors, and etc. BTW earth is an extremely good protector against nuclear radiation. 3 feet will give you a PF of 1000, which means that it will only allow 1/1000th of the radiation in. IIRC.
You also get into ventilation and such with that.
Anyway, sorry guys, if this was more in depth than the OP was intending, then Oh well, I felt like writing an essay.