Setting a character's course of action is rarely a simple act of pointing the MC in one direction and pushing him along. Quite often a far more important part is to cut off the paths he might have gone instead and making certain your readers know why he didn't take the easier way.
Easier, of course, is rarely the better choice for a story. However, harder can look manipulated unless block off other directions. If your character decides to cut through the woods on the way to the castle, rather than take the path that leads straight there, give a good reason that will make the other path not the best one. Here are several I can think of for this simple set up:
1. There is someone who lives along the path whom he doesn't want to see.
2. There is someone in the woods he hopes to meet.
3. It's the short cut (a usual reason, but good if he's running late).
4. He's not going where he says he's going, so takes a route that keeps him out of sight of others.
5. He wants to get to the castle before a wagon reaches there, so racing through the woods while it goes up the main path will work for him.
There are five reasons he didn't take the path. Now, what happens to him in the woods is another matter. You know something is going to happen, but why then and there? That's another case where you have to close off other paths to make certain this one is viable. Yes, there is chance in real life. Unfortunately, we rarely accept it as readers.
So just make certain once someone heads one way, it is because it makes sense, not just because that's how you want him to go as the author. The great part is that we, as authors, can do anything in our world to make it reasonable.