It's my belief that she went out to the car that morning and someone was there. Forced her into the car and drove away with her.
Did something unknown with her for 2 hours and half (from 6:45 am when she left home to 9:14 when they were at the gas station).
Stopped at two more gas stations. LE is also saying that her ATM card was used multiple times, including gas stations. To me, this means that it was used at OTHER types of locations too, but they are keeping that info secret. More than likely, LE has an ATM hit in the location they keep saying- they keep letting us know that she may have been in such and such area (sorry I can't remember the name at the moment).
Then, the perp did something even more horrible to her- and drove her car to the Walmart location.
In my experience, Walmart parking lots are huge. They always have the spots shopper actually use and the spots too far away that no one uses. At our local Walmart, it is very common to see many one or two big rig trucks there (their drivers probably sleeping), an RV (maybe for the same reason) and maybe one or two cars.
Also- it has been pointed out that in Oregon you can't pump your own gas. That means that the gas attendant was close to the car. Surely, he or she would have noticed a gun, a gag, rope, a dead body if there was one.
