I agree with just about everything you said here. Nice post. My gut, though, with what little I do know about the case, still says she died by accident or medical issue. What you say makes perfect sense about how most people wouldn’t go for a long walk right before a bunch of people were expected at their house, and if they did, they would likely bring a phone with them just in case someone called. But two things could explain her walk without a phone- 1) if she left the house well over an hour before her guests were to arrive and she only planned for it to be a quick stroll around her immediate surroundings, and 2) she was known by everyone to frequently take walks. Maybe it was like 3:50 pm, not long after she talked to her son, when she left for her walk. And maybe she planned on taking a quick route she had taken dozens of times before that she knew would only take her 30 minutes round-trip. If that were the case and she wasn’t looking to take pictures but merely to get a little fresh air before the temperature dropped at sunset, then her walk before a party and without a phone would make sense.
The reasons I shy away from something criminal happening are: 1) her age (most women targeted by predators/perverts/killers are usually quite a bit younger), 2) the safe area in which she lives, 3) the time of day the crime would have had to occur (risky to pull off with people out and about at that time), 4) no signs of a struggle anywhere inside her home or outside along any paths, 4) the limited time frame which a crime could have occurred (son talked to her at 3:20 and she was gone by approximately 6 pm or so, and 5) how well she was liked by literally everyone (no grudges seemingly). Sure, people have been victims of crime under a few of those circumstances many times. But that’s a lot of conditions present for a crime to occur. The odds of a random lunatic or serial killer/predator wandering the streets at that very time of day and encountering her seem pretty low. Likewise, a situation where some stalker had been following her for days and then decided to strike that very day during that very window of opportunity seems pretty low on the probability scale. And if some nutjob did kidnap her... why? No ransom demand was reported. I can’t see a larger woman in her 60’s being a target of some kind of sick hostage for pleasure situation either. Just for the sake of stealing some jewelry she had on or just to kill her for fun? I guess maybe that’s a possibility.
Outside of those types of crime, I guess that leaves a contract killing ordered by someone she knew. But I’m not getting that vibe at all. It is a bit odd the lack of outcry coming from the family and friends, but not altogether unrealistic. There have been other missing persons cases discussed on here where people were wondering the same thing- why friends and family weren’t begging for help or answers in the media. And in many of those cases, the missing person ended up dead by accident or suicide, and the family had nothing to do with it at all. I’m like you, though. I’d be yelling from the rooftops every moment of every day until my loved one was found.
As you correctly stated, the ocean is a powerful and unforgiving force. And any time someone goes missing very close to a large body of water like an ocean, river, or lake, seemingly more times than not that is where they met their fate.