re: unmanned vs manned
There is a good case for a broad unmanned program as part of any exploration or exploitation in space, but there are advantages to having people on the scene, too.
For one thing, you don't grow old waiting for unmanned systems to accomplish something a human presence could do a lot faster.
The Mars Rovers between them have clocked about 16 miles in five years. Each of the three Apollo manned lunar rovers easily equalled and beat that mileage in three or four hours of operation. Granted, the Apollo drives didn't have anywhere close to the number of long stops for research the Mars Rovers had, but humans still get things done a lot faster.