How often can 汉 be used for the English -er, person who does ____? Google Translate¹ gives 流浪 for to wander or wandering which is supported by other sources, but for wanderer, tramp, hobo it gave 流浪汉. That was surprising, but I did find a source that said 汉 could be used for a person.
Is there a not-too-complicated way to know when to use 汉 instead of 人？
¹Yes, I know that reliable machine translation is still science fiction.