i would add a spill cleanup kit to your list. at least some oil absorbant and a garbage sack to pack out your contaminated dirt.

the list looks good to me. it doesn't seem excessive. i would throw in some spare lugnuts and since your taking a tire plug kit, you probably should take some type of air compressor to fill your tire back up.

i don't usually pack that much stuff on trail. i usually 4 wheel in areas where camp is nearby. i don't even take a spare tire. if i need something, i just get a ride to my trailer and get it. if it's a big run like jamboree or something, i'll take a bunch of stuff so i can fix quick and not hold up a group.