I've been thinking about the chain of events based on the evidence we have at hand at this point in time and I think the abduction of NG may have proceeded in the manner below. This is based on there being just the one Perp.
The Perp has left his car on the roadside nearby and has walked onto NG's property and has spent some time quietly scoping out the house and neighbours houses to ensure all is quiet. If the pic of the Perp not wearing the backpack or holstered gun is real and not altered by the FBI, then the Perp stood in front of the porch entry for a moment before backing off to gear up, possibly using the intervening time to test whether NG is receiving or responding to doorbell camera alerts.
The Perp then walks up to the front door and proceeds to disable the nest camera (1:47am), taking his time because he knows that no one is responding to the alerts. He then walks back to his car and drives it onto the point in the driveway where NG's later blood trail stops. He gets out of the car and proceeds to walk down the western side of the house, past the garage and enters the back gate between the main residence and guesthouse. Here is where he may have been spotted by another camera at 2:12am (i'm unsure whether this is the same nest camera or a separate camera due to conflicting media reports).
In the backyard, he then disables both floodlights against the back wall of the residence using a heavy object, possibly a lump hammer or something similar that can fit in his backpack. He then enters the house through the glass sliding door (the easiest point of entry and apparently early reports state it was found wide open). Once inside, he has less than 16 minutes to rouse NG and bundle her out the front door and into the car so that she is beyond the reach of her pacemaker app by 2:28am.
So based on this timeline which to me, seems to fit the evidence we have so far, the Perp didn't spend much time in the house with NG and it looks less like a robbery gone wrong and more like a targeted abduction.
Anyways all the above is MOO.