I have ADHD and will occasionally get hyper focused on prepping and organising, one of my best ones was my car.
I have a little tiny Yarris and the boot is quite small.
I got one of those boot organisers with 3 boxes that takes up the width on the boot and leaves about 30 cm in front or behind it for longer things.
I also have filled the little storage jar thing that came with it with parking money.
So always in my boot are,
Box 1 - PPE kit for work (2 boxes gloves, pack aprons, 2 boxes masks, visors, spare paperwork and yellow clinical waste bags.
Box 2 is a bin, always lined with a bin liner, I can't stand having a messy car.
Box 3 is the every eventuality box and has,
Wipes,
Petty cash,
Rolled up towels (the thin absorbent gym ones)
Sanitary towels, deodorant, toothbrush and paste and a mini hairbrush,
Mini first aid kit with added sun cream, tweezers, scissors & paracetamol,
A spare vest top, hoodie and leggings for me.
A blanket that can double up as picnic mat.
A few bottles of drink & snacks.
Power pack and lead incase my phone dies.
Spare glasses (I can't see without them)
A book,
Pencil, pen and notebook and sellotape.
I always feel safe and prepared in my car, I hate driving the bigger family car because it's a tip and it doesn't have my kit in it.
We're going away next week and I'm going to stela a few of these mentioned by others.
Also we're another family who love to take a flask of hot chocolate or tea and a hot snack on a thermos.