Finally checked out Valley Truck Center (Bellevue, NE) after seeing their lot on my commute for months. They keep around 80 vehicles, mostly work vans and fleet vehicles. They were totally fine with my mechanic doing a once-over, which honestly settles half the trust question.
Lot address: 1110 Fleet Way, Bellevue, NE. Visitor parking: Front-lot customer stalls facing the office; overflow on the side street near Bellevue lot gate.
Paper side: licensed with the state (looked it up), about 95% of stock has title in hand per the office, and they offer a 6-month powertrain warranty on newer units.
Overall: good people to deal with. 18 years in business around work vans and fleet vehicles, doc fee $449 and it's on the window sheet, no games. I'd send a family member there.