I would do the front brakes first. Aluminum radiator.

Then an aluminum water pump housing, Moroso or Meziere water pump.

You can lighten your K-member with a little fab work (or send to Bondo Bob). Fab or buy some aluminum bumper brackets.

I see a passenger seat in that pic, can you lose any more weight in interior?

You can reduce resistance with light wheels and tires, gun-drilled axles and lightened gears, AL driveshaft, rollerized trans, synthetic fluids, but it will cost you plenty of $$$.