You're traveling on a hiking trip in the land of Landilandia when you encounter a forest. The notes in your guidebook tell you that there's a safe route here leading into the woods, but when you approach, you discover that there are actually two paths to choose from. Beside them are three men sitting outside of a tent, engaging in some sort of friendly card game.
The first man looks up as you approach. He immediately hails you, cheerfully saying "Be aware, traveler: if you enter this forest, you take your life into your own hands, for at least one of these paths will lead into peril!"
"Uh, thanks," you say. You look back and forth between the left path and the right one. "I guess this trip might not be as simple as I was hoping."
Then man laughs, then adds with a wink: "And seeing as you're probably hoping to find out which path -- if any! -- might be safe to travel, you should know that one of us is a knave (who always lies), one of us is a knight (who always tells the truth), and one of us is an alternator (who strictly alternates between lying and telling the truth)."
What an odd custom! You had read about people like this in books, but this is your first time meeting any in real life. But you re-check your trustworthy guidebook, and it confirms that this is indeed so: men in this particular region of Landilandia always travel in groups of three: one knave, one knight and one alternator (and naturally they know which of them is which).
However, your guidebook also notes that there are strict social rules on foreign visitors such as yourself interrogating the locals. Asking questions that can't be answered with a "yes" or a "no" is considered a grave insult, and asking too many questions would be tantamount to picking a fight (and you're pretty sure you wouldn't win).
How can you find a safe path into the forest with the fewest questions possible?
And a followup question, if that one is too easy for you:
Even though you don't strictly need to know in order to travel safely through the woods, you can't help but wonder which man is the knight, which is the knave and which is the alternator. After a brief internal struggle, you finally come up with a compromise between your curiosity and your politeness: How can you find a safe path into the forest and correctly identify all three men's roles at the same time, without asking the men more than one question each (i.e., not more than three questions total, one per man)?