My objective is to make a sweep path for creating the ground part in the assembly.  This part has no life outside the assembly.

The path is like a belt tangent to the construction circles.

The Make Path command cannot read my mind; it seems I have to trim out some arcs from the circles.

Trim to closest has worked for me in this situation in other documents, but in this document the arc removed is not the arc selected by the mouse pointer.

Alt-PrtScr does not capture the mouse pointer in this graphic, but the SW scissors are near the bottom of the 240 dia circle just to the right of the tangent point with the straight line.  The brown color arc being removed is remote from this.  Each arc to be trimmed is as crazy as this one.

This same tool works properly on the polygon.

Any suggestions?