Wally World special, eh? If you try to start upgrading things as they break, then you'll end up spending a fortune for, what in the end is, a WW special. I'd just replace the broken spokes in that case- carrying a few spares and plenty of tools for the Arizona trip. Better yet, for a nice reliable ride get an older mid-level used MTB of some quality marque like Trek 820 or Specialized Rockhopper for about $100 off Craigslist, and tune it up. The wheels, frame and components will be way less prone to failure. Plus it will weigh less, shift better and generally be more pleasant to ride.