Well, I would simply replace the pinion shaft seal and then I'd remove the C clips and slide the axles out. Move the axle bearings with two fingers and feel for any grittiness or odd feeling. If there is none, and if the axle doesn't wobble up and down in those bearings I'd replace the axle seals, put the axles and C clips back, get a new gasket and put the back on. If those axle bearings feel weird and gritty, go to RockAuto and buy yourself 2 new bearings and replace them plus new seals. You can remove the bearings using a special slide hammer puller or ... you can get a 3/4 inch bolt, a couple of heavy duty large washers (one of which you'll cut with a hacksaw to be able to work behind the bearing and pull them out that way. I wouldn't waste my time sandblasting anything. Remove the brake line and clean it with a steel bristle brush plus an old rag with gas to remove any old grease, oil, etc. Then paint it, put it back in the truck and use it. Those gears may be fine. They've worn in happily and with new oil probably won't give you any trouble. See what it does and then make a decision. Wash the pumpkin out with a little gas if you want but if there was no sand, metal chips, etc in there, you may not even need to do that. Check and service the brakes (including parking brake) while you have the axles out.
