I was able to email enginediy.com and got a reply in about twelve hours. They provided a 17travk link with the so-called last mile tracking number. Soon afterward the USPS indicated the parcel was on the move from CA. As has happened frequently of late, USPS is very slow uploading tracking events. By the time they indicated it had gotten to the local PO, it was on my porch. Twelve days, end to end, arrived in reasonably good condition.
Thanks to all for your indulgence.