The "do-gooders" are only concerned with someone's outer image.  Pap's appearance can change but that does not mean that his mind set will.  The judge who took Pap in only gave him a better chance to get custody of Huck and better access to alcohol. 

Huck's father is an old man in his fifties with gray, ratty hair.  He wears clothing with holes and patches.  Pap has holes in his boots and a cross with nails on the left heel to ward off demons.  The holes in his clothing corresponds to the holes in his memory form when he was drunk.  The nail cross tells the reader that Pap is a man who believes the devil is coming to get him.  In chapter six, Pap believes the angel of death is there to retrieve him. 

Huck was able to go to school, see his friends, and sneak out when he lived with Widow Douglas.  However, Widow Douglas had rules for Huck to follow.  Huck had to wear nice clothes, not swear, and not smoke.  When Pap kidnapped Huck, Huck was able to smoke and swear at the cabin.  On the other hand, Huck was not allowed to leave the cabin for any reason.  Huck's living situations traded freedoms.  He traded structure for no rules, and he traded the ability to leave for being trapped.