It is down at the bottom end of Greenford Avenue, between there and Drayton Green Station. The roads are called Tennyson, Allingham, Milton, Shakespeare, Cowper and Dryden -- hence the area name.

I've lived in Cowper Road for 28 years!!! and really love it.
We have lovely neighbours, a brilliant Indian Restaurant a couple of minutes walk away, lovely local parks and walks, good schools and it's convenient for buses and trains.
The 'local' pub is The Roundhouse on the golf course which has the potenial to be brilliant but never quite is (though it does have a lovely garden with a great view) which is why so many of us are impatient for the opening of the new wine bar. 
The Cuckoo on the corner of Drayton Bridge Road does wonderful food at very reasonable prices and so does the other cafe (the name of which escapes me).
I walk my dog every evening very late and have never encountered any trouble.
My only word of warning would be keep your car well locked up, but I suppose that goes for anywhere in London.