The family used boats to check the entire shoreline, both for evidence that SS fell in and for her body. Granted, this was weeks after the fact, but signs of someone slipping or signs of her remains would very likely be visible along the shoreline. Bodies don't usually sink unless someone makes sure they are weighted down or they get caught by something underwater.
We don't know how far she could walk, but the family indicated that she would have to be driven to go any real distance. The marina is across the road, but it's not a short walk for someone disabled. I can't speak for Stacey, but walking even relatively short distances is painful for me because of back problems, so taking a walk to the marina would not be something I would do for pleasure. Pain puts a damper on enjoyable activities like that. Of course, she
may have attempted to go for a walk and gotten into trouble, but in that case, she wouldn't have gotten too far. Her BF's property and surrounding area has been searched.
Anything is certainly possible, even if it doesn't seem likely. But in my observation of the cases of disappearing women (and even men) in the Emerald Triangle and southern Oregon, it is generally caused by someone else, rather than by an encounter with nature. Of course, proving it is an entirely different matter. I'm hopeful that LE is looking at all angles. It can often take many months before there is enough evidence to name a POI. It took two months to name Lennie Ames a POI in Stephanie Warner's disappearance and two
years for the sheriff to say she was probably dead and to name him a suspect. If you hide someone well enough, you can usually get away with it.
JMO