Grease on stuff doesn't mean much. Cracks on component's boots doesn't mean the components are bad, just that they aren't well protected. If you don't like the grime you could pressure wash it, though that can force water into stuff.
The front driveaxle joints at the knuckle are prone to problems on those, especially if the boots are torn: symptom would be noise in the front suspension on sharp turns.
The lower control arms on those are prone to hardening up with age and causing really crappy steering. Tie rods and ball joints are probably fine unless they have play, usually pretty reliable. Shocks you should be able to tell from driving it, if the front or back ends wallow around like a boat in choppy water, might need shocks. If there's clunking or hard engagement moving from froward to reverse, or vice versa, the differentials might need work.