How does the owner of the car feel about you doing 100mph on this 400mile run?
Motorway junctions are more than regular enough. Perhaps plan your journey beforehand so you know where you're going to come off.
But you can risk doing 100mph? It's easy enough to stop at a roadside cafe or even a layby and stand outside and drink your coffee.
breasts... 288Ah, it's just that when you said "this is someone's personal vehicle", I presumed you meant that it was someone's...
An option available at any speed of course...
I highly suspect that 70mph is going to return better mpg than 100mph!
The date seems to be relevant to your story, I suspect it affects the amount of services present on the journey and as you've said above, it affects the air-con in the car.
It's also interesting that in order to find a story to attempt to justify the speeding, you've had to go back well over a decade! Even if I agreed with you on this scenario, it hardly makes a case for casual speeding above the limit in general does it!!
So you yourself admit that you don't "need" to do 100mph? Then don't. Simple as. Go to bed earlier, set off earlier.