I think a lot of it has to do with your location. I am from MT so I will use communities there (feel free to check out google maps to find some of the locations I mention or if you have kids and want to get some map practice in dig out that old atlas collecting dust some where and have some fun.
If your in Yellowstone County which is the most populated county in the state and you have access to costco, sams club, 2 target stores, 3 walmarts, 5 albertsons and 2 iga stores plus a number of clothing stores and other types of stores then a 3-6 month supply for most people is going to be sufficent because even if your on a ranch outside of Custer, MT once you reach town your 56 miles to Billings which is the largest community and the county seat. This is figuring that there are going to be days that there is black ice on the interstate and local authorities are going to issue emergency travel only restrictions and since that is very much a ranching community (maybe 2-5% work at the school or at the local bar/resturant) trips to the city are reserved for such things as medical, dental, vision appointments, school supplies, holiday shopping, and when your team is playing in a basketball tournament.
On the other hand if your on a ranch outside of Opheim, MT where it's 51 miles on a state road just to Glasgow and 319 miles to Billings (closest large town though Great Falls is not much further at 322 miles) a drive that on dry roads is just under 5 hours each way your going to want a stock of at least basics that can last you from mid to late September clear through to anywhere from mid April to mid May. While it is rare we can get snow fall that early and that late though usually those are short storms that clear out. At the very least you need to plan on needing supplies to last mid October to mid March.
While you can get some supplies in a small town the price is going to high. A 4 pack of scott brand toilet paper (name brand but on the lower price end) that costs $3.97 for a 4 pack at Walmart in the Billings or Great Falls area would run you $5.95 in a town like Glasgow or Havre and $8.76 in a town like Opheim because of the issolation of the town and the local stores are going to be much smaller and thus not have the room to stock a huge amount and variety.You might find 2-3 at most brands or varities of toilet paper, toothpaste, dish soap, laundry detergent, spaghetti sauce, pasta (there is macaroni, spaghetti or angle hair depending on what they have, lasagna, and if you lucky either penner or rigatoni you want shells instead of elbow for that macaroni well sorry your out of luck) and rice (choice of brown, white,or instant in small bag or box only) plus a small amount of canned fruits and vegetables (peaches, pears, pineapple, fruit cocktail, green beans, peas, corn). While you can get flour and sugar it is going to be small bags and you are going to pay a much for that 1-2 pound bag as you would for a 10 pound bag of the same brand in a larger community.
not talking some fancy specialty blend-simple marinara.
Hopefully I get around to it soon. I have some large airtight storage boxes with gaskets that I'm thinking about using under our beds. Normally I wouldn't store pantry stuff in bedrooms but I was thinking since they are supposedly airtight they would keep bugs out too.
