We were "dual rated" on 707s and VC.10s-during my time there- in the mid 1970s.
The standard VC10s were being phased out-but did a fair few trips on them still.
At the time I was there only stewards were allowed to do the freighters-but I seem to recall it changed after I left.
It was a tiny galley-and certainly not a standard one-as fitted on normal 707s. There was a small oven and some stowages for food containers plus a hot cup-for boiling water,a stores cupboard and that was about it!!
Before departing (overseas destinations only) -the steward would contact the Captain and ask if they had any special food requests-and certainly at places like Hong Kong/Tokyo etc-you could then order pretty much anything-the crew wanted (Lobster/Pheasant etc etc) and as long as you had an alternative choice of menu for the F/O or F/E-pretty much anything was available. Needless to say-we ate well too of course. There was also a small amount of cigarettes and half bottles of spirits available for the crew to buy if required.
There were two double galley jump seats-one forward and one rear facing-but no passenger seats at all. You could squeeze down the side of the cabin-to visually check the cargo (in case of smoke/leakages etc??).
Carried a White Rhino on one occasion with an Indian handler-and he sat on one of the jump seats.
Most of my freighter trips-I would be invited to occupy the cockpit for take off landing. On arriving at destination overseas-the crews would usually split up as Flt deck and cabin crew would in most places stay in different hotels.
Some of the flight deck crew in those days were old school still and wanted there to be an obvious class differential (them and us etc) but mostly by then things had begun to change and most flt deck crews were seemingly embarrased to have to leave you on your own for a few days-until you met up again for the next leg and would often invite you to meet up in their hotel etc the next day.