They might as well start making their tissues functional, and, bit by bit, build towards synthetic humans that can be used as very lifelike robots. Or why not grow actual organs and put them in?
The need for all the support "machinery"? Lymphatic system to dispose of waste, vascular system to pipe food and oxygen, oxygenation for the blood, glucose production, hydration, temperature regulation... These are hard to implement because the scale from the macro to the micro - from inches in diameter to microns.
woah there, why don't you slow down on the hard science and just let me enjoy West World over here?
Don’t forget the hard parts... self-replication, energy storage and conversion, damage sensing and repair.