The Motion Boutique shows how you can attach a layer to the end of a path in After Effects.
Arrowheads, type, leaders and more; There are more than a few tools that let you attach something to a line in After Effects. You can also choose to build the setup using expressions manually. Check out this post from the folks at the Motion Boutique that shows how you can create a set up that will attach a layer to the end of a path.
Attaching Things, From Simple to Complex.
The article covers the absolute basics for attaching something to the end of a line. You can then plus the set up by adding things like automatic orientations, how to make arrowheads, and more.
Check out the article for some trim path tricks showing how to attach a layer to a path here.
Motion Boutique Connect Layers Pro.
OF course, if you don’t want to fuss with all the code, you can use Connect Layers Pro. Motion Boutique’s script lets you create lines that are dynamically linked to the layers using powerful path expressions.