I have been in a 124 a couple of years back. It was in LGB and the whole plane is truly impressive. It has a huge rear cargo ramp and there are actually two internal cranes rated at 5 tonnes - if I remember correctly. The cockpit was mind-blowing as well. I remember the 12 green "gear-down-and-locked" lights. Behind the cockpit there's a section for the FE, Navigator and fro two other crewmembers. Behind that compartment one could find resting beds.
Unfortunately, I don't know if the ramp can be opened in flight.