Farragut's operations at Vicksburg were wrapping up before the Arkansas ran the gauntlet. The bombardment wasn't working and the falling river doomed Williams' canal.

I don't see how the Arkansas alone could break the blockade. No single ship could do that. It could drive blockaders farther from a port for a time, but it could not stay on station indefinitely. By this stage of the war breaking the blockade was not the primary aim, disrupting Union offensives and protecting assets was.

The Arkansas was no CSS Virginia as its run down the Mississippi had shown. By comparison the Arkansas' armor was inferior and had been penetrated several times--producing very heavy casualties. The USN's 9" smoothbores gave her more difficulty than the Monitor's 11" Dahlgrens gave the Virginia.

That's not to take away from Arkansas' accomplishment of running the gauntlet to Vicksburg. She caught Farragut's force flat footed and ran with the current, pummeling the wooden or lightly armored craft along the way. However, she was far from invincible and had to obtain a new crew to replace the dead, wounded, and those lost back to their army units. Down the river the USS Essex most likely would have finished her even if her engines had not failed.

Had she succeeded in running to New Orleans what could she accomplish? She had no base to operate from and N.O. wouldn't be recovered by a single ship. A run to Mobile was risky and she might very well have proven unseaworthy, particularly with battle damage and if hounded by warships. If she did make it to Mobile then she would have improved the defenses there, but Mobile didn't fall until 1864 anyway.

The CSS Arkansas is a good example of the extreme threat that an ironclad could pose. A bold commander could create absolute chaos. Unfortunately, a single ship could do little to exploit this beyond a short tactical advantage. If the ironclad tried to fight a prepared enemy it would most likely be lost. In contrast, by engaging in bold but less committed action the vessel could be preserved. By continuing to exist an ironclad could play an important strategic role in disrupting Union naval and even army operations.