In a topographical context (ie, directions to the bank), I think that a native speaker would say "Are these the right directions?" (or, more formally, perhaps, "Are these the correct directions?). "Is this a good direction" does not sound natural to me at all -- both because of the singular "direction" as well as the use of the word "good" instead of "right" or "correct".
That said, it is interesting that Polish uses the word "dobry" (good) in this context. French is like Polish in that regard: "Est-ce que ces directions sont bonnes?"(literally, "Are these directions good"?).
Query how you would say "the right answer" in Polish. In French, again, the most natural thing to say is "la bonne réponse" (literally, the "good answer").
I've made "the right direction" the default option.
If I understand your "directions" correctly... is that like: "go straight ahead, turn left by the post office, walk for 218 metres and then turn right"? Or drawing a route on the map with your finger? Polish "kierunek" is just: left/right/straight/north/south-west etc. A general notion. To denote something more specific, we'd say "Czy to jest dobra droga/trasa?" (Is this a good route?)
"dobry" works for "right" quite well. You can also say "prawidłowy" (correct, proper), "poprawny" (right, correct), sometimes "właściwy" (proper, appropriate). All four of them (after you make them feminine, of course) sound perfectly fine to me for "the right answer". Translations taken from English Wiktionary.