I have always been under the assumption that couple=2, few=3. (approx.)
This being said, would one say, "two of apples"? I feel the"of" is unnecessary.
However, if you were, let's say...choosing varieties for your dozen donuts, it would be appropriate to say, "i'll take a couple of these and a few of those". "A couple these and a few those would be incorrect.

What i'm trying to say is, the English language can be confusing as all hell sometimes!!!!