I found the issue. The '3D Visitor' was stationed way off in the distance, which apparently counts as an item on the plan. The visitor was unable to get all the way up to the house. But, I was able to move him / her closer, save, reload, move closer still, save, reload, and now all is as it should ...

Thanks.

The plan got somewhat smaller, but it still ranges from 0 to 6400 feet, and 456 to -1890 feet. I cannot see any objects scrolling around the border.

I attempted going to each level, selecting 'all', deselecting the house by holding shift & dragging across, and then deleting the remainder ...

Is there a way to reduce the plan size to fit around the house?

Somehow, while attempting to do a 3D walkthrough, the plan size expanded from about 3 acres to something roughly 4 square miles. It is very difficult to find the house in all that.

I'd love to get it back to the 3 acres ...