JDK
The former Howard Hughes DC-6 with Northern Air Cargo is serial number:
45372 and registered N7780B
The reconnaisance aircraft you are talking about is the Hughes XF-11. Hughes crashed and nearly died in the first prototype but at least one other was built.
I am looking foward to the new movie about Howard Hughes even though it stars Leonardo di Caprio and the Hughes H-1 replica will sadly now not be available after the tragic crash which killed the owner. Recently saw a TV serial about Hughes starring tommy Lee Jones which was excellent and feature a host of rare aircraft.