Here's a possible scenario:
We don't know exactly when Jen became missing the day of 12/11/12. We're assuming she left around 10:00 to drive to the mall, as reported.
GR's publicly stated "air tight alibi" includes going to the Y in Norwich and entering the sauna, where he runs into an old friend (state trooper). He doesn't normally go to the sauna, but did this day, because he didn't dress for the weather, which is odd because most outdoor enthusiasts up here check the weather forecast first. I think he pre-staged his alibi. The first part of his alibi involves being on the computer while he was alone in the house with his wife for two hours, after their children were off to school (presumably by bus). He states he can prove what he was doing because he was emailing for work (working from home).
Anything could have happened in the home during the times he *wasn't* emailing for work.
Jennifer's car is then found on Route 23 in Norwich. The YMCA that GR went to was less than 1/2 mile away from the car. It was also reported in local papers (I'll look for the link) that GR was seen jogging that day in Plymouth (which is near where both JR's car AND her phone were found).
It's possible that GR drove the car with JR in it for at least part of the destination, to it's final location at 98 Plymouth St., Norwich NY, jogged a few miles away to dispose of her phone, and then went to the Y to "thaw out" and then jogged home. GR was the last person to see her alive, and the only person who stated her alleged plans to go shopping at the mall.
This seems far more plausible than a depressed, formerly devoted mother leaving her kids. Depression is paralyzing. Even making plans for suicide is sometimes exhausting. Not saying she's suicidal, because if she were, she had the means to off herself at home (gun in the home, as posted on her FB page). Every step weighs a thousand pounds for someone who's depressed. And yet GR wants the public to believe that JR concocted this elaborate plan to leave, even though it was far more beneficial to stay and end the marriage (she would get the house, 1/2 of all other property/assets, pension, etc., 1/3 GR's income in child support, etc, etc). He has an affair with her best friend, he asks her for a divorce, she begs him not to divorce her, and then poof, she's gone, like someone else mentioned here on WS in a much earlier post. It just doesn't add up. Even statistically it doesn't make sense.