"what should i take in spare parts.... stuff that breaks frequently." Explorer stuff doesn't break frequently.
Your explorer is mostly stock. If you don't stupidly hammer it hard I don't think you'll break anything. I've driven cross country several times, wheeled hard, and still made it home. I cannot imagine how you would break a driveshaft unless you purposely went on a trail way more difficult than an almost-stock Explorer should be on in the first place. Stock and almost-stock Explorers by the dozens from around the country have gone to Moab for our events and made it home.
The following assumes you are going to stay on moderate trails since yours shouldn't be on an extreme trail in the first place: besides all of the equipment listed in my
Trail Equipment article found on this site, the only things extra I could think of would be a spare hub and ujoint - you might blow a ujoint, but not a driveshaft. I've gone through three thermostats and it would not be nice to have one go out on the trail, so pack one of those. Spare serpentine belt, hoses, etc. Pack one of the centerpin bolts that line up your rear leafsprings onto the axle perch. One time someone bent an outer tie rod, you might think of packing one of those. CVs are going to cost - you have separate left and right front driveaxles and will have to pack one of each, and they ain't cheap, so if you want to plan for that, pick them up used at a junkyard for maybe $100 each as trail spares, with the 1/2" drive breakover and huge socket you'll need to take your axle nut off with. Since you don't have a front locker and big tires to add stress, your CVs should hold as long as you don't hammer it with the steering turned full left or right. The only CVs I've seen blown by any of us didn't occur until after we had modified way beyond the 31" tire/TT lift stage.
The thing is, your Explorer probably won't break. I've lost count of all of the Jeeps and other vehicles I've seen break stuff while I was wheeling my almost-stock Explorer with them. And most of the Explorer breakage I've seen involved modifications made to the Explorer, not the Explorer itself (lift kit brackets cracking, etc).
Be prepared, but enjoy your trip. You'll do fine. The only thing extra I can think of is that it might be a good idea to learn about the trails you will be on. I don't know most of those trails, you might contact Rick or Hammer or other Arizonians to find out if any of those may be too extreme for you.
EDIT: Check and tighten all bolts, etc. I asked this same question awhile back after nearly having a critical one back out and wanted to know what else I should pack. Not too much response on that thread either; like I said, your Explorer is pretty tough.
http://www.explorerforum.com/forums/showthread.php?threadid=48040&highlight=break