When translating from English to Latin or Greek, I developed a “rule of thumb” to distinguish relative clause from indirect question: Before the apparent relative word (“where”, “who”, “when”, etc), insert the words “the answer to the question”. If the result (apart from sounding officialese or interrogationish) makes grammatical sense and has the same meaning as the original, it is an indirect question. How accurate would such a rule be?
How could it not be? It’s the same as asking yourself if it’s an indirect question.
That long of a thought process may hamper reading speed.
I think a better “rule” is to examine why the relative is there: does it have an antecedent (explicit or implied) or does begin a question?