Re: If a spacecraft COULD enter a black hole, how could it travel in time?

If a spaceship entered a black hole everyone and the ship would be destroyed.  The gravity would rip the entire contents to shreds.
Because a black hole is so massive, the difference in gravitational force between head and foot would be enough to pull things into thin strips.

Of course, the other side of the black hole's event horizon can never be known (at least that is the reasonable theory).  The event horizon is the radius from the 
center of the black hole at which nothing, NOT EVEN LIGHT, can escape.

Time travel is really not possible because once the ship is inside the black hole, it will not return.  

You may want to look up the effect of gravity on time.  There are a few readable books and web sites on it.  Look under relativity.

Sincerely,

Tom Cull