You can create a custom polyline fabric. Here is an example of someone using fabric to create a dashed arrow: sandcastle. Please visit our wiki on Fabric here.
Another way you can approach this is to concatenate multiple arrow lines together.
Thank you for the details! Here is a basic sandcastle demo to get you started:
In this demo, I showcase how to use CZML Polylines to construct lines with arrows. I am using a CZML Point for the waypoint. Alternatively, you could use the Billboard object.
I am glad that I was able to help you out with a sandcastle demo. Your screenshot looks amazing! Thank you for sharing this with me. If possible, we would love to see your completed project when the time comes. We are always looking for community work to showcase and celebrate!