I, perhaps mistakenly, made a path a stroke (path-to-stroke), now my drawing has 3 lines instead of just 1 for the outline of a part. So when I export to a dxf (which ultimately goes to a waterjet for cutting), it is useless because it looks like a part in a part and I'm really struggling trying to figure out how to get back to a basic shape that only has one line for the outline.

Please help!!

Hi.

Some manual edit you will need to make.
In general, here is something good for the start.

I guess it's too late to just Undo? Or too complicated or large to draw the path again?

Yep, the only way to get it back, if you can't undo or draw it again, is node editing.