I can consistently drive the ball over 300 yards and I'm 6'2" and 168lbs (measured this morning). I think a twenty handicapper could do it, but they wouldn't have much control over it. In fact, a lot of golfers I see just rip the ball of the tee, but can do nothing else. A couple of times this summer I played with people I didn't know and was out to have fun, so I pulled driver on pretty much every hole just trying to go for it, mainly from their encouragement. Can't tell you how many times I have heard "I've never seen anybody drive this green before". And I read somewhere something about 9 irons from 150-160... thats a pitching wedge for me, maybe a smooth 9 iron, but I could get a PW that far without too much umph.
btw, I'm not a 20 handicapper, but there are bad golfers who hit farther than I do.