

For the box:
Birth certificate, passport, emotionally important and irreplacable things. Bringing some food / water ofc is important, given the risk of heat strokes on hot days.
In terms of where I flee, I pick some nearby towns that are basically kilometers of concrete and ashphalt, and not right next to a forest. Talk to some friends that are in safer areas before hand about potentially staying over.
Another option for me is to go the city, and just book a hotel.
Try focusing on life in general tbh. At age 80/90 (hopefully!) You’ll likely be so done with life its easy to accept its end. At least, thats what it seems like talking to the older folk in my life.