I carry spare shaft assemblies for both sides of the D30, a spare 8.25 shaft, a spare driveshaft that can be used front or rear, spare u-joints, spare heims to cover all of my steering, spare tire, plug kit, serpentine belt, drain pan, funnel, shop towels, hand cleaner, assortment of fuses, electrical tape, roll of 16 gauge wire, and good assortment of tools. Mainly just a nice husky tool kit in its container plus assorted pliers, crescent wrenches, pry bar, breaker bar, and a few specific sockets for the unit bearing nut and bolts.
That stuff along with my recovery gear should get me back to the trailer or trail head no problem. Like George mentioned, always go with at least 1 other rig. That way even if you have to leave the Jeep behind to get parts you have a ride home.