i've driven up to just past the Arctic Circle in 2020, and up to the NWT border in 2021. (as far as we could go during NWTs lockdown).
July will be the best weather, but really buggy, and likely muddy.
August will be busiest, but less buggy and muddy.
Early September should be the best drive and view, although there is 100% the possibility of overnight snow or frost. But likely no mosquitos.
The road surface changes quite a bit depending on the section, as the fill comes from each other, and the geology varies greatly. The worst is the last 100 km before Eagle Plains (sharp shale like rock)
The mud will build up really badly due to the spray they use on the road, so pay attention to how its accumulating.
The road will go from smooth and perfect to pothole hell, in 100 ft. So you don't let your guard down.
The drive through the Tombstone area up to through the Ogilvie is incredible, and among my favorite of all time.
Most of it is safe for Grizzlies as long as you use common sense. Although i wouldn't camp at Engineer Creek, as that area seems to have high aggressive activity.
We traveled with a spare, plug kits, and tire foam/fix.