I was a training captain for many years in Big Airways in the days when it was possible to let friends and the public have a go at flying a B747 or B777 simulator. Private pilot or microsoft expert or not, even with a talk down, none succeeded in getting the aircraft anywhere near a survivable landing on a runway despite several attempts. A PPL might get the B747 into the semblance of a flare, but the landing would either be dangerously fast or slow, the flare too high or too late and almost certainly into the scenery rather than on the runway. The chances are about 1 in a 100 of getting it right. You would be sensationally lucky if you did. At best you could prevent an uncontrolled descent from altitude and you might enable a few people to survive the controlled crash.
As a training captain on the classic I have seen some screwed up attempts by ATP pilots to land the plane as well.
It is not a difficult bird to fly, it just takes some practice.
As for the topic of this thread: Back in January I was in the B-747-200 simulator in MIA flying the right seat.
In the left seat we put a PPL with about 400 hours of Cessna time.
He was to do a take-off, a few steep turns, some other airborne maneuvers, then come back and land, all night and VMC.
Don't remember if the chap had an instrument rating or not.
At any rate, he was able to do most of the maneuvering somewhat within some limits, but it took non-stop talking on my part.
What surprised him was the stick forces when out of trim and the constant need for trimming the stab.
He was able to do a radar vectored approach to final, then some sort of a landing when talked to all the way down.
If he was on his own, it would perhaps have lasted 2 to 4 minuttes before over-controlling with total loss of control and structural failure.
He was not a bad pilot, even Chuck Yeager would have screwed the pooch in that scenario..Too much to learn in too little time.