The journey between 48 to 55 may be the easiest of the day.
With luck the vehicle traffic may be so busy as to be staionary,
based upon a combination of being a designated route to Heathrow, (to the non-locals/unknowing), people piling into the Tesco at Hayes Bulls bridge and B&Q Yeading.
It is a purpose built bypass to Hayes, with wide lanes, and a good road surface.
(Local legend also has it that the young Bradley Wiggins used it before the road was finally opened, as it is adjacent to the Hillingdon cycle track).
I'll try and get out along it this weekend, to see how suitable it is.