To be clear, Orthuz, let me give you a non-sarcastic answer. Because I’m not trolling, I’m being serious.
Blizzard is good at broad world-building, but details such as distances and travel times are never elaborated on. Outside of specific situations. You’ll unfortunately likely never get a canon answer. My best guess? 2 weeks? Just based on various comments and such that I’ve seen, it seems like that’s about how long it takes to get from Kalimdor to EK, and vice versa.