For panel-mounted components (connectors, switches, potentiometers, etc) I have created parts with the appropriate schematic symbol, but named something like “Switch, SPDT Panel Mnt Interface”. The associated footprint is simply an array of pads on the PWB - where the connecting wires will be soldered. (Or, where a pin header will be installed.) When I place the component (switch, connector, etc) on the schematic I may mark it with a text field pointing to a drawing note (e.g., “See Note 5”) and the field of drawing notes gives information such as “5. Off-board component mounted on front panel.”
Dale