I always carry a 200+ piece tool set, fire extinguisher,3 gallons of water, gallon of power steering fluid, trans fluid, brake fluid, 2 gallons of antifreeze, gear oil, screw jack, hi-lift, multiple sizes of coolant hose, first aid kit, cooler full of food and beer, drinking water, lots of wire, connectors, snap ring pliers, hub socket, spare mini starter, toilet paper, duct tape, electrical tape, spare front axle shafts (not currently for the D60) hard brake line, jumper cables, air down tool, power tank,pick set, snap strap, 2 come-a-longs, ratchet straps (big and small) some misc wood blocks for jacking and pounding, towels, gloves, sun block, bug spray, extra light bulbs, flashlight and head lamp, spare output shaft and probably more stuff I can't remember.
I have all of that in the Bronco at all times - I carry more stuff in the tow rig. I've got to slim it down a bit - not sure I'll trust it all without the top on... I like to be prepared...