Way Point Visualization Via Editor Mode
If you download my Victory BP Library plugin, which contains my Vertex Snap Editor:
You can see how to make your own Editor mode!
You can then draw lines in the Editor Mode DrawHUD function and have access to the Editor Objects which are your various waypoints that are all linking to each other via pointers.
This is the way to go if you really want to just draw lines in the editor without adding extra components and/or scene proxy code.
I am simply offering this as an alternative to the component-based route for you to consider, plus I have all the code already ready for you in the form of my Vertex Snap Editor plugin 
Have fun today!
Rama