
The temperature (which I really didn't set much score by) needs to drop significantly, and stay down. When it does that, whelping should begin within 24 - 48 hours. I went by the time from the first mating - and yes I know, conception doesn't necessarily happen right then. And I didn't let mine go over by more than 2 days without involving my vet.
Mine didn't start nesting until labour began - small ripples can be seen.
Puppies with mine tended to go 'quiet' shortly before whelping started and the first time I noticed this, it scared me to death but I assume it was just them getting lined up ready to come into the world - and resting before that too

It's good she doesn't have lashings of milk - newborn puppies don't need much and often can't cope with overloaded teats.
Good luck! And try to catch up on as much sleep as possible before it all kicks off