How does he avoid this?

Huck tells the family all about the Sawyer's and entertains them with stories. Soon, he hears a steamboat coming down the river, and realizes Tom is probably on the boat, since the family was expecting him. Eager to meet his friend and keep himself safe, Huck tells Aunt Sally and Silas that he must return to town to fetch his baggage, quickly explaining they need not accompany him.