Mike, you and your son going to love it. My advice on spares depends on how your getting your zuk there. We bring a spare everything to camp except a motor. On the trail I would advise a minimum of a rear driveshaft. On the trail I bring front and rear axles, hubs, driveshafts, fuel pump, fluids, tools, bug spray, and pray I don't need any of it. Don't be fooled when your informed that the Green trail is the easiest. It's challenging, has more than element of excitement, and the distinct possiblity of body damage. On the other hand, bone stock sammi's make it all the time with no problem. You just have to know when to bypass an obstacle. You will want to make sure that you have good yank points front and rear. You will want to bring plenty of water out on the trail also. You and your son will have the time of your life.
Scott Whitmore
"Share your knowledge. It's a way to achieve immortality." Dalai Lama