He could save a bunc of room by just letting his wife and daughter take the Jeep.
The ice chest ONLY holds soda? Man that's a lot of sodas. You really should be able to feed 4 people for several days with that one cooler. Including drinks. Too much cooking gear for 2 people. On top of that a grill? Two plates, to sets of utensils, one dutch oven and you should be good. If you plan ahead and make the meals before hand then all you have to do is cook them. Tables? Most of the time we're eating from our chairs around the fire. Portapotty, yeah, learn to do it the old fashion way with a shovel.
I don't think Girl Scouts take that much baggage with them camping.
I think for spare parts, you really have to think about what's got a high chance of breaking and what you can live without, even if you're limping in 2wd. Having too many spares may help in the 100:1 shot but for the 99 other times it's just an anchor.
With two people, and spare parts/tools, you shouldn't have it stacked much higher then the sides of the Jeep.
i usually take more than he has just for 2 pple
i have 2 coolers, 1 full of drinks (pop, water, beer^2) and a plug-in one with food (meats, cheese, eggs and stuff like that), i have a huge (no j/k) tarp that takes a lot of room, another small tarp, bbq, tent, sleeping bags, inflatable matress, table, chairs, tools, travel bags, 2 jerry cans with water, propane, inflatable boat, small and big hatchet, 1 bin with a lot of little stuff like starter fluid (for the fire), lighters, travel plates, knives/forks, etc. - like i said, packed up all the way to the top.
usually use all of it except for the propane tanks, i have taken twice as much as i used every time.