In chapter 17 of Andrew Clements' A Week in the Woods, Mark begins thinking about the consequences of his actions for having not gone to Mr. Maxwell's truck but headed up the Barker Falls Trail instead. He starts thinking about all of the commotion he will cause. He pictures his caretakers, Leon and Anya, being called, the private boarding school he will soon be transferring to being called, and all the kids at the camp being sent home because a search party needed to be organized to look for Mark. Picturing the kids being sent home from the camp marked the real turning point in his thoughts; he couldn't bare the thought of spoiling the week for the rest of the kids. Therefore, he thinks that the best solution is to make his way back to camp as fast as possible. The decision to get back to camp is one reason why Mark changes directions. Yet, the trail is not what he expects; therefore, he decides to change directions a second time.
After having walked about one-fourth of a mile up Barker Falls Trail, Mark stops to rest and studies his map. He discovers that another trail "looped off to the left from the main trail and wound back down to the campground" (p. 127). He finds the new trail very easily and heads off in that direction.
In chapter 18, Mark has been hiking the new trail for thirty minutes and is getting tired. The trail makes a "sharp turn to his right," and at that point, he sees that it goes up a steep hill but is also no longer really a trail: "It looked more like the rocky bed of an uphill river" (p. 131). He decides that route will not really be the safest and wisest route, so he consults his map to find another way. He sees that if heads straight to the left, in the direction of west, using his compass, he'll reach the part of the trail that heads downhill towards camp. So, Mark decides to leave the loop trail heading west.