I worked for 3-D back in 1998 and it was great. If it's the same run then it's BIL-HLN-APA (denver), sit from midnight to 4 am, then APA-BIL.
7 hrs of block a night, usually 3 nights one week then 5 nights the next week. Autopilot and radar worked, safe company, Billings is a great town.
Not sure about the Ameriflight part, at the time 3-D was an independent company contracted to Security Armored to do the Norwest (wells fargo) runs. With the closure of the AMF BIL base they might have picked up one of the old AMF runs.
PM me if you'd like and I'll give you more details and contacts.
