Use a DIY stethoscope. A 6ish foot length of 3/8 tubing in one ear and earplug in the other. Point it around to "sniff out" the noise. Someone else would have to drive.
On the doors, did you do the metal door and the skin?
For the floor I recommend Lizard Skin spray. You're going to have everything out and it's a more cohesive coverage.
Big yes to guard dog!! Camera alert will be triggered a lot if you have cats and wild animals around.
People still cover faces in public if needed. In my state that argument wouldn't be good enough. Now a drop gun or knife . . . .
Motion activated lights are not a deterrent for thieves. They are helpful for the Police IF they happen to be passing by.
If your light goes on while sleeping are you going to jump out of bed and check? Camera's we're effective 20yrs ago when nobody knew. Now criminals wear face cover. Alarms...
When I first did some extensive sound deadening/proofing to my vehicle I didn't have a meter BUT 75mph now felt/sounds like 60mph.
As far as engine noise I haven't seen any under hood insulation. Improve that and add a "D" gasket to the back and you'll hear the difference.