Hello Eddie G
I also rode the old D/D buses on Fifth Avenue -- the Queen Mary class.
You may have ridden one of the few remaining OPEN TOP 1930's era Double Decker Buses on 5th Ave. I rode the Queens Mary's in the early 1950's to the end of their operation by some time in 1953. I DID later ride the one SAVED Queen Mary on a few special private trips... when it was under some form of private ownership. After an accidental "run away" (or "roll away") accident in what, the 1980's, near W. 43rd Street, it's front end door-side was damaged and it later eventually became part of the NYCTA (MTA) antique historic bus fleet. Its damage was perfectly repaired to original condition and it has been run on special events. I took photos of it inside in the 1980's before the accident -- you had to walk stooped over on the upper deck which was only about 5 & 3/4 feet high from floor to ceiling. I was 6'3" then (and am still now)
I well remember that the rear seats at the back end on the lower deck of the bus were much higher than the others, and the floor was higher also along those seats across the rear window -- because the motor was back there. On a few trips in 1952-53 I recall a distinct faint odor of DIESEL Fuel and fumes in the rear area of buses in operation. Seems I never forgot that ! If I recall, they were STICK SHIFT buses and slow and lumbering. The stairway was immediately behind the driver.
regards - Joe F
