Ok, so the waypoints that the boat has passed (that cause a crazy tail route) are from "Non-active" routes. I can obviously delete those with no problem and can also use the cursor area tool and right click to delete multiple POI/waypoints on that non-active route while being careful not to affect the active route.
I have managed to add a POI to the active route. It always seems to want to add somewhere in the middle depending on the "Sequence Number for the Route".
IN an ACTIVE Route with the VLM-VMG checked.
To Add a POI to a route: Put your cursor on the Route where you want the new POI. Right click and pick "Place a new mark". The Mark Dialogue box comes up. To have this mark become part of the route, select the Route name from the dropdown, an pick the sequence number [I can't seen to get this to work
right, the POI is always in the wrong order]
To Edit a POI in a route: Highlight the POI Green Box with the cursor, right click and Pick Edit. The typical Mark dialogue box comes up. I checked not simplifiable because I don't want it to Move (I need to pass the WP3 properly.
It is not clear when a New POI in a route will show up as a Green box or not. They all seem to be hidden even though Not Simplifiable is checked and Hide Intermediate POI is unchecked.