Not sure what else Amflight does though I'm sure it's more than just UPS. I think they have a web page if you search for it.
The Convair was a kick. I flew them out of LAX mostly, a little out of SFO, and always into LAS. It was a night mail contract run by Evergreen in late 80's. I lived near the beach in LA and loved it...good thing the job went away and I got furloughed or I never would have landed at UPS....
I went from 500 hours in light twins to the Convair....all training done in the aircraft. It was a handful for me but I got good training with a company that gave a crap about their pilots and I made it okay. I made Captain in about a year and got about 400 hours in the left seat...my only pic turbine time to this day......