Is this the best line possible?  It came from the chess mentor and I thought I made the right move (first move) but it wasn't the move they had in mind.  :)

As I recall, this is from one of Spassky's games.  And he played here 1 Nxd8 Nxf5 2 Nc6 and his opponent resigned.

 

Your line seems pretty promising too.  Although at the end Black can play 7... Nd6, and after 8 d8/Q Nxe8 9 Qxe8 he is hanging in there at least (though clearly a bit rickety). 

I think both moves are winning. I also came up with your move, though I found it not so easy to calculate all the upcoming onslaught.

 After looking at it with the neutral help of a chess engine, I think spassky's (if it was his) solution is at least faster. Is a faster mate always more elegant?  I don't know.