You should be able to shift OUT of gear anytime, whether the clutch is disengaged or not.  With the engine off you should also be able to shift INTO any gear pretty easily without pressing on the clutch.
Like 
@5doorsoffury said, disconnect the shifter cable linkages at the trans, and see if you can shift in and out of gear easily.  Also see if the shifter in the car moves freely - it should flop around like a pornstar's dick pre-Viagra. 
Did the builder crack open the transmission at all?