I'm just having a tough time imagining the scenarios with such little evidence, honestly. I listed them all out before but the only ones that have ever really spoken to me are suicide (if she'd battled depression, that might be why her mom's family hasn't spoken out as much; they could possibly suspect it) or abduction.
This appears to be the Walmart she worked at, based on a case map:
https://www.google.com/maps/search/...ata=!3m4!1e1!3m2!1slJYcZws7e7_OD8TkewAB2g!2e0
In street view and satellite, it appears as though there is no side parking lot for staff; it's the same as customer parking. So then, everyone should park within view of the cameras. Has LE ever mentioned even looking at surveillance? If not, then I don't think she made it to the Walmart at all, otherwise I think they would have said so. I also think that means that she did not meet up with anyone there.
IMO I think we can count out her ever getting to Walmart.