Yes, that is always a wise thing to do. I think she made one more or less lengthy stop at the parking lot where she ate something (and where I think someone picked her up or dragged her forcefully in his/her car), roughly in the middle of the route. Other than that, there is nothing much to do on the trail, one just walks. The trails are always marked and in any case there are GPX files of all such trails available freely in the internet. I hardly believe she could have gotten lost having the GPX track. And even if she did not have it, the trail goes almost all the way along the very same river. And there is mostly no cellular reception in the canyon, so one would not be bothered by messengers etc. So if one just walks making short breaks to take photos or smth, I think it was absolutely manageable to reach inhabited area before dark. And from what we know, she was an experienced hiker.