just clean it up nicely!
Clean it all up....Perhaps CRANK SEALS.
Keep it basically stock and RIDE IT.
Maybe an expansion chamber (difficult to find......my '71 still has the one that was on it when I purchased in '74 or so) and a fork brace.
FRESH fork juice..grease steering head bearings AND SWINGARM BUSHINGS.....maybe rear shocks and a brighter headlight.
VERY RELIABLE MOTORCYCLE!
Clean and grease all electrical connections.......Buy a spare CDI box off ebay.
1973 slash 5 toaster