Maybe it goes without saying, but I pack the Prius for the occasion. So, for example, when I w
ent to Quartzsite in for a couple of week in January, I didn't pack mosquito repellent because I was in the dry desert. But, I did pack a 10x10' tent awning for shade, ease of dressing, personal care and cooking. I didn't pack the tent, however, when I was on my 2010 6-month cross country trip because I wasn't planning to stay for than a couple of nights in any one place.
So, the packed items listed below are for a specific 10-day trip to explore a National Park in early spring.
Glove boxes: spare glasses (sun and reading), monocular, binocular, sewing kit, safety pins, emergency seat belt cutter w/window breaker, small note pad, weather radio, owners manuals
Dashboard: SPOT GPS device teathered to small stuffed dog
Pocket hanging from dashboard: pens, pencils, cell phone, momentos
Slot below radio: lip balm, nail file, pill box,
Jockey box: inverter, computer power cord, toothbrush charger
Floor of front passenger seat: 1 gallon of water, kitty litter, tire chains, duffle bag with extra food
Front Passenger Seat: Pantry box (see page on nourishment), small blanket, water bottles (including one with a filter), hatchet, duffle bag with toiletries, duffle bag with cleaning items.
Front Passenger Seat Back (laid flat): sleeping bag, bear spray, heavy flashlight, pocket knife, two plastic drawers (bottom w/food; top with electronic stuff, battieries, pens, pencils, compass, whistle)
In contrast, here are 3 blog posts specific to how the Prius is packed when I plan to stay places for weeks at a time (vs. doing a lot of travel).
How the Prius is packed when stationary: http://suanneonline.blogspot.com/2015/04/part-1-packing-prius.html
How the Prius is packed when fully loaded and driving: http://suanneonline.blogspot.com/2015/04/part-2-packing-prius-for-travel.html
How the Prius is packed when fully loaded and sleeping/lounging: http://suanneonline.blogspot.com/2015/04/part-3-packed-prius-for-sleeping-and.html