We've covered the standard 5 C's several times on here so it's a pretty easy task to figure out what would work best for a relatively short stay of 48 hours. I would also contest that you would have your regular EDC on you, but you must use you REAL EDC stuff, not that load of crap you put up on instagram when the new hot hashtag pops. Since I'm not able to carry a handgun inside the facility and it's a federal crime to do so. Outside the controlled facility, where I'm currently parking, is not violating the law, so I'm going to call it part of my EDC. Glock 26 it is. Also, I keep a get home bag in my truck, but that would really muddy the waters, so it's out.
My EDC is- Ghurka wallet, G Shock solar watch, Phone, Keys, Prototype Weber folding knife, Work pants, usually Blackhawk, 5.11 or Kuhl. SOE, uncle mikes or an official BSA belt, Darn tough socks, Danner work boots, Mechanix cold weather gloves, Blackhawk! fleece beanie or a poly stocking cap, Carhartt Quick Duck Jacket with a hoodie or fleece under layer. I do EDC a flashlight, but it's pretty unconventional because it's a Thrunight headlamp. I have to work in low light areas that require me to use both hands all the time so a regular flashlight doesn't work.
The best way I can think of is to work the problem backwards. You can live 3 seconds without safety, 3 minutes without air, 3 hours without shelter, 3 days without water, 3 weeks without food, 3 months without companionship.
-Air isn't an issue in my neck of the woods, so we can leave that be.
-Safety, on the other hand, is a prerequisite of the preparedness lifestyle. I'd go with hiding for safety in such a short stay, but I do count on my handgun.
-For shelter I'd bring a Sil-Nylon tarp of the 10x8 variety.
-I wouldn't bring any water, but instead bring a container that I could readily boil water or cook with. For sure I'd choose the Self Reliance Outfitters Canteen kit.
-With the weather being pretty cold out and my EDC consisting of my work attire, My Carhart jacket and underlayer isn't going to be enough to keep me warm at night, so I'm going to bring a Military Sleep System. This system could even be used as a stand alone due it it's gortex outer shell that is water resistant, but I prefer to be able to stay dry outside the bag as well as in it.
-I'm going to have to kill a few birds with one stone and call out an MRE as well. It has food, TP, gum, condiments and most importantly, matches inside.
-My last item would be cordage. 7 strand paracord or bankline.
Why is this system going to work? Because I cheated. Multipurpose or multi item units are cheating, but that's the rules set out with ITS. If I wasn't able to cheat, I'd have to simplify and go with these alone.