I would do it in these stages if your doing stages, im just saving up and stock piling parts why i dd my rig around.
1. bumpers,sliders,cage
2. weld rear end up add a winch
3. sas because you realize ifs sucks for what you do and dual cases at the same time if your terrain calls for it( no need to change shafts 2 times.
4. save for awhile after spending all your money on the previous stuff.
5. gears and tires do it at the same time because you know going bigger means gears will need to be changed now, and since you only welded the rear up no money was spent in buying a locker do so now if you must.
6. longs and hub gears
7. stand back and look at your mean looking yota.