Is there an easy way to do a telestrator type of drawing on the screen over video in Vegas Pro?
You could use an animation tool to create a file that emulates the drawing process and add that to the top track of your Vegas Pro project. Make sure the drawing has a transparent background so that you can see through to the video on the track below. Alternatively, you could use the Chroma Keyer filter to key out the background so you can see through to the track below. You could also use an animated mask to reveal an element over time, which can often be used for drawn-on effects. You can add to the number of points in a mask as you go.