My BOB does doubly duty as an ARES/RACES jump kit...so it’s more COMMS specific
But in no specific order:
1) FAK with trauma kit
2) 3 days food and water
3) change of clothes
4) can of sterno
5) heat reflective tarp
6) lighters
7) glow sticks
8) flash light
9) hand warmera
10) 100’ paracord
11) mechanics gloves
12) small fixed blade knife
13) write in rain notpad
14) basic toiletries kit
15) 2 hand held ham radios with roll up j-Pole antenna
16) spare batteries
17) small basic tool kit
18) small compass clipped to outside of pack
In the truck I also keep a mossberg 500 and a SW shield
Whatever kit you build... keep it light as possible.... and try hiking with it....a pack that’s bearable in mile 3 might be agony by mile 6
Carrying 50lbs might be fine when you are dry cool and comfy.... but when you are tired, injured, and it’s hot and humid.... it’s gonna be misserable