It means that is not work that everyone wants to do, but he is happy because he is easily making a lot of money. It is a saying. Think of "laughing all the way to the bank" as a set phrase. You can't change the words and keep the same meaning. Hope that helps!

'Laughing all the way to the bank' - Its a phrase/saying which means someone is making money very easily! You can't use it with other places. Hope I helped!