Re: How did the Nero, his crew and ship escape Rura Penthe?
Since it was all deleted, the whole Rura Penthe subplot involving the capture of Nero is non-canonical. From the point of view of canon, it never happened, and so Nero and his crew never escaped, because they never spent any time on the prison planet in the first place.
Which then brings up the question of what the hell were they doing for 25 years if they weren't in a Klingon prison?
"Your present circumstances don't determine where you can go; they merely determine where you start.' - Nido Qubein