Yes, Bilbo Baggins did visit Erebor again. After his initial adventure with the dwarves in "The Hobbit," Bilbo returned to Erebor to attend the coronation of King Dain Ironfoot. This event is mentioned in the appendices of "The Lord of the Rings" and shows that Bilbo maintained a connection with the dwarves and their kingdom even after his first adventure. **

Bilbo Baggins is 50 years old at the beginning of The Hobbit. **

Yes, the dwarves from The Hobbit did visit Bilbo. They came to his home in the Shire to recruit him for an adventure to reclaim their homeland from the dragon Smaug. Bilbo initially resisted joining them but eventually decided to accompany them on their journey. **

Bilbo suddenly becomes young again in The Hobbit because he is a hobbit, and hobbits have a longer lifespan than humans. The ring that Bilbo found and kept for many years, the One Ring, also has the power to prolong the life of its bearer. When Bilbo finally gives up the ring and leaves it behind, he begins to age at a normal rate again. This sudden rejuvenation symbolizes Bilbo's release from the corrupting influence of the ring and his return to a more natural state. **

Bilbo, Frodo, and Gandalf sail to the Undying Lands with the ship. The Undying Lands, also known as Aman, are a mystical realm in the west of Middle-earth where immortal beings such as the Valar and the High Elves reside. It is a place of peace, beauty, and healing, and is said to be outside the circles of the world. The journey to the Undying Lands symbolizes a final departure from Middle-earth for those who have completed their quests and seek rest and solace. **

Frodo Baggins is a character in J.R.R. Tolkien's The Lord of the Rings series. He is the nephew and heir of Bilbo Baggins, and he inherits the One Ring from Bilbo. Frodo becomes the central character in The Lord of the Rings, as he embarks on a quest to destroy the Ring and save Middle-earth. Bilbo Baggins is the protagonist of The Hobbit, which is a prequel to The Lord of the Rings. He is a hobbit who is content with his quiet life in the Shire until he is swept into an adventure to help a group of dwarves reclaim their homeland from the dragon Smaug. Bilbo discovers the One Ring during this quest, which sets the stage for the events of The Lord of the Rings. **

Bilbo, Frodo, and Gandalf are sailing to the Undying Lands, also known as Aman. This is a mythical place in J.R.R. Tolkien's Middle-earth where the immortal Elves reside. It is a land of peace and beauty, free from the troubles and conflicts of Middle-earth. The Undying Lands are also the home of the Valar, the powerful beings who helped shape the world. **

Bilbo Baggins did not go crazy despite the challenges he faced because he possessed a strong sense of resilience and inner strength. His hobbit nature, characterized by simplicity and contentment, helped him maintain his sanity even in the face of great adversity. Additionally, his experiences on his journey with the dwarves and Gandalf taught him valuable lessons and helped him grow as a character, enabling him to overcome the challenges he encountered without losing his mind. Lastly, Bilbo's sense of humor and ability to find joy in small things also contributed to his mental well-being throughout his adventures. **