Gokarna is mentioned several times in the Mahabharata as a place of pilgramage and is eulogised as such, for example:
... Then one should go to Gokarna, renowned in the three worlds. O Indra amongst Kings! It is in the middle of the oceans and is worshipped by all the worlds ... on worhsipping Ishana there and fasting for three nights, a man obtains a horae sacrifice and attains the status of a Ganapati. A man who lives for twelve nights becomes pure of soul ...
Dhoumya, a sage, says:
... Gokarna is famous in the three worlds. O son! There is a lot of water there and the wayer is cool. It is sacred and auspicious. The lake is extremely difficult to access for men who habe not purufied their souls.
However, moksha is not mentioned in close connection with this. It is mentioned towards the later closing chapters where Brahma himself discourses on it. In fact, it's related through Vasudeva who is replying to a question by Arjuna who asks
the Brahman is the supreme object of knowledge and you should explain this to me.'
And Vasudeva replis by saying:
there is a record of a discussion long ago between a teacher and his disciple on moksha ... his disciple asked, ... where have I come from? Where have you come from? Tell me about the supreme truth. From where do mobile or immobile creatures originate from? How do creatures remain alive? What is their lifespan? What is truth? What are austerities? What are the qualities of those who are virtuous? What are auspicious paths? What is happiness? What are wicked deeds?
In this discussion he relates that a number of maharishis visit Brahma regarding this question and Brahma himself says:
All mobile and immobile things are born from the truth. O ones who are excellant in your vows! They live through austerities! Truth is always united with the qualities and has the five manifestations. Brahman is truth. Austerities are truth. Prajapati is truth. Creatures are born from the truth. Creatures possess the greatness of truth. That is the reason brahmans resort to the truth ... one who understands the truth about this is patient and knows the truth about the creation and the destruction of all beings. He is not overcome by confusion. A person who knows the exact truth about the attributes, the qualities and everything about the gods is cleansed of all sins and is freed from his bonds. He obtains all the unblemished worlds.