Expert here. You will need several tiers of supplies.

>Medical
CAT tourniquets, 2 chest seals with vent, oral and naso airways, gauze (lots), quik clot, sutures, steriglue, basic wound treatment and cleaning, CPR bag, trauma shears, SAM splint. This is a good start and you'll be able to handle 90% of trauma with interventional care.
>Weapons
Handgun in 9mm with spare mags and 1000+ rounds, shotgun for breaching with 250+ 00, AR with 12+ mags 2,000 rounds. 5" fixed blade (non-serrated!!!), small blade for skinning/field craft. Multi tool. Level 3+ armor with PC.
>Water
Several week's fresh water storage in case you need to stay in some days and avoid visibility. Lifestraw. Grav filter. Lifestraw is good for a go-bag and procurring individual clean drinking water, but not larger quantities. That's what you need a grav filter for. Both will take nasty water and make it clean and drinkable. They filter 99.9997% of contaminents out.
>Food
2 months of freeze dried food with canned meats. Opt for SPAM, canned corned beef, etc vs canned tuna/salmon as it is higher calorie content and cheaper
>Other basic supplies
Lights/headlamp with spare batteries, pens, cold weather gear, 20 degree sleeping bag, r4 sleeping pad, solo tent/bivy, gloves, chapstick (undervalued), lighters (fuck a flint - just buy several bic lighters). Also, get an MSR cooking kit with spare fuel tank.

>Gear setup
In a go bag, you want 72hr gear. Things to get you INTO some shit, and get others OUT of some shit. Your medkit, firestarter, spare mags/ammo, lifestraw, lights, hothands and basic cold weather gear, small amount of food, both knives and firestarter. The idea of a 72hr bag is you carry it with you every day and it gives you mobility to move overland if you have to gtfo.
>Long term gear
A solid framed bag capable of carrying a 40-80lb load. Pre-load tent, sleeping bag, sleeping bag, cooking kit, addl cold weather/rain gear, spare mags and several days food. Transfer go-bag equipment and roll out.