The trace always goes through the point on the entity you used to select it. If it goeas around all the coast except for the section you want, it is an indication that you didn't select the entity to be traced using a place inside that area.

I am not really understanding what you mean when you say you can't "see the actual path"? When using extensions with insert building, it asks you for a point inside the house, and then the edge of the house. First one doesn't require a preceice placement, and the edge of the house should be clear enough. I don't think I really get your problem here.

When deleting the walls from the floorplans, I recommend hiding the floors sheet first. The floors will have the exact same edges as the walls, making it easy to select them instead. Also, remember that lines are selected by their centerline, not the edge. This is important if you are closely zoomed.

If you click the add-on buttons, that will often change the symbol filters. The fastest way to go back to the default settings is to re-open the map, since this loads the settings again. And the quickest way to do this is just to first hit save, then pick the top option from the recent map files at the bottom of the file menu (the current map should be the top one)

You can also open more than one window in CC3+, and these can have different zooms. They don't offer different rotations, and they will have the same set of sheets visible, you you can't hide a sheet in just one of the windows.

You find this under View -> Windows

While there are tools to help you easily/automatically draw a city, there isn't a way to automate the drawing of the walls. A normal city is seen from above, so you see what you refer to as the roof drawing.

But for making the "interior" view, you will need to draw the walls/windows yourselves. The house symbols doesn't have removable roofs that reveal readily-made interior. It is easy enough in CC3+ to hide the roofs (or more accurately, hide the building symbols) to reveal what's beneath, but you will need to draw that beneath part yourself, otherwise you would just stare at a blank area.

I guess you could use the automatic floorplan generation to help you with this. When you generate a floor plan from a house (only works with proper CD3 symbols), a separate drawing is created with the walls of that building. Those walls could then be copied back to the main city drawing and placed under the house so that they are revealed when hiding the house. It will be some manual work doing this, but it at least gives you the building outline for free