AF1 are both regular 747-200 powered by CF6 engines.
They are not much different from "civilian" 747s... oh yes, a few details.
xxx
The differences are that they are able to do air-to-air refueling.
They have the regular "10 tanks" for fuel system, as some ailine 747 have.
Self contained airstairs are located in the FWD cargo compartment.
The main difference would be in electronic equipment, radio/communications.
It is possible that the generators are higher output for these extras.
xxx
The flight deck pictures I saw, show no differences with a regular 747.
Analog "steam powered" round gages - like I used to fly.
Probably some updated FMS have been added for updated avionics.
Pilot training probably done at PanAm Academy for simulator and instructors.
Specialized training done "in-house" obviously by USAF.
In the AF1 "707" days 1970s/1980s, TWA provided training for the pilots.
xxx
I believe AF and LH 747 pilots could more or less fly Air Force One.
BA pilots, operating RR engines, would require CF6 differences training.
xxx
Happy contrails