Though I wanted to come up with a well written travelogue, this thread compels me to respond as someone who also ended up driving the Golden Quadrilateral on the same day when the duo (Bhaskar and Prabhakar) started from Bangalore.
The only difference here was the fact that we broke for the night 4 times and drove 2 continuous nights and successfully (should I also say safely) completed the circuit in 7 days and 18 hours.
Here is the snapshot of my sector speeds in each leg and the car being my humble Wagon-R which had clocked 1,67,000 kms on the Odo when we started this drive.
The whole drive was taken up by a single driver (Me) and I was accompanied by my father and my cousin as co-passengers.
I am sure there would be many who would then begin to think why a Wagon-R and I would still say "why not" when I am the only person behind this trusted tallboy's wheel since it is in my garage.
A safe car may be unsafe behind a rash driver and an unsafe car can save you from death if you drive it carefully. I have been following the same principle ever since I have taken up long drives on this car.
Coming to the topic in discussion here:
While it is so easy to start guessing on how dangerously could the duo be driving without proper sleep, It is also a matter of few spared minutes of thought and a good experience on highway driving that can make one realise that not necessarily one needs to hit beyond 3 digit speeds to get the best average per hour.
If we are talking about short distances like Bangalore-Chennai or even Mumbai-Pune, I do agree that faster driving shall bring down the travel time considerably. But in a case like this where we are talking about 6000kms in one go, IMHO, it is impossible to be able to be speeding all throughout the drive as the body simply cannot take it. Eventually, every driver will settle for a comfortable cruising speed (which definitely cannot be 130-140). After all, you don't want to be breaking from 140 to 40 and start all over again when you spot a truck changing lanes or a pedestrian crossing the road or a biker swaying out of the shoulder.
Additionally, clocking the best average speeds is also a matter of the time of the day one passed certain sectors. Driving very early mornings and late nights can phenomenally bring up the average speeds without crossing doubtful limits and will still make the driver behind the wheels feel comfortable and will not result in much fatigue as otherwise. I covered most of the sectors at night and that gave me a fantastic driving average. Overall, the driving only average excluding breaks is 75kmph which is not bad at all. My usual cruising speed varied between 100-120kmph and little more than that wherever road conditions and traffic pattern permitted. All through the drive, I could have never even thought of driving faster (by pushing myself and the car) to reach a destination on time and you can see that we have reached all our destinations past midnight.
If you see my sheet above, I drove continuously from Mehsana till Varanasi (1750kms, 31 hours) but took ample breaks. The second longest drive in a single shot was Vizag-Bangalore and again with breaks.
I could have never even attempted to be rash, give a hint that I was sleepy or being irritated as I was with my father who has been my companion ever since I took up driving (he has never driven all his life) and one mistake today means a trust broken after so many years.
Our initial plan was to start from every place at 5am but as you can see from the sheet, one single late start on the first day had a cascading effect on the rest of the days since we needed proper rest (at least my 60 year old father must).
*I deviated off GQ from Ahmedabad to take Mehsana-Palanpur and touch the GQ again at Udaipur to accommodate a social reason