Bushmill
All the world's freighters have no acces to the back, and no extra crew to draw on.
ON a long haul flight the extra crew would already be foward with the cockpit crew. On a short haul flight the reason that airplanes have two pilots is that in the event of the loss of one, the other can land the aircraft. That is the whole point, or we would already be down to one pilot in the cockpit like on the Cessna Jets...
There is nothing to be checked in the back. If there is a question, LAND the airplane. There are actually virtually no pilot serviceable parts in the back of a jet, and is just for peace of mind. But if you got that serious a question, land the jet and let an engineer look at it. As far as landing Gear down locks go, that can easily be done with cameras.
Wino