Given that her husband indicated that Stephanie had issues with alcohol, and given that the Walmart video showed her purchasing a bottle of vodka, my first thought was that she may have blacked out and driven off a highway somewhere - with the Tahoe perhaps ending up deep in woods or in/under some water located adjacent to whatever highway she was traveling on (probably on her right side of the road).
I don't know if the Tahoe had On-Star, but if it did, I think that LE would have been able to locate the vehicle by now - especially if it were in woods somewhere off of a highway. I don't know enough about On-Star and other GPS systems, however, to know whether LE could use those systems to locate a vehicle that was submerged.
My guess though is that LE has looked (and is still looking) for any evidence that a vehicle may have left a highway along any probable route which Stephanie may have taken upon leaving the Walmart (if that is what she did). Sadly, I think a lake located immediately adjacent to a medium speed, slightly-curving highway, is the most likely scenario/location.
That said, the Ring video posted by Sissymay now has me scratching my head. That sure did look like Stephanie: right hair color, black shirt, black/dark pants. And if I'm not mistaken, she had what appeared to be a clear (vodka?) bottle in her right hand.
Has anybody been able to confirm that the woman seen in the Ring video at N Chickasaw and E Colonial at 5:31 am on 10/5 was in fact Stephanie? After the woman walks around the front of the white car and then walks past the driver's side door, she appears to toss a clear (vodka?) bottle in the direction behind the car. Had she been in the car drinking before the Ring video begins (had Stephanie just gotten out one of the passenger side doors)?
If the woman in the video was Stephanie, she appeared to leave that location in the dark, and on foot. This might bring an abduction scenario (or other mishap/ accident not involving the Tahoe) into play.
So to me, the first question is: was that Stephanie on the Ring video at 5:31 am at N Chickasaw and E Colonial on 10/5? If it was, I am less inclined to think that she maybe blacked out and drove her Tahoe off a highway somewhere into woods or a lake - and more inclined to think that some other accident/mishap may have occurred - or that foul play could be involved. All JMO
I hope Stephanie is found safe, and soon!