Why did Tom want to go with Huckleberry
Answers
Tom is not nearly as naturally goodhearted as Huck is. He certainly doesn't share Huck's sense of altruism and compassion for strangers. For this reason, it seems very ironic or even suspicious that Tom would want to help Huck free Jim. The fact is that Tom simply enjoys adventure and putting his plans into action. He also knows that the adventure in particular comes at no personal risk to himself.
He knows this because unlike Huck and Jim, Tom is aware that Jim is already technically a free man, having been formally freed in Mrs. Watson's will. This allows Tom to seem far more heroic than he actually is, all while having Huck indulge his over-the-top and elaborate plan. He gets to enjoy his adventure without having to actually buck against society.