Yeah I think it's better to aim for your knees to travel not in line with the toes, but further out the the side of the feet. Doing this while walking up stairs helps to.
And as you say Alexus the knees can come forward over beyond the toes. I think once your knees are travelling in a healthy path, the most important thing is to focus on keeping a good back position. Focus on keeping the thoracic spine erect and strong, for example.
This video is helpful (Ithink someone above has already mentioned it). Well worth a watch: