Mason can be used with TinyCad to simulate a design, output the microstrip lines and packages with a proper net list, even when that design includes non-simulation elements (see the schematic below, or download one of two examples below).

Instead of using the GND component in Mason, it is possible to use the built-in ground in TinyCAD (Power Tool Options, near the wire tool for drawing connections) if the Power Voltage is named "GND".  The only reason I put the ground port in Mason is to avoid having to type "GND" (one less thing to go wrong, as well).

Just as devices can have a "Package" or "File" parameter, devices can also have a "Nodes" parameter.  This allows a device to have more pins in the schematic than are defined in the simulation.  Consider the schematic below: the amplifier is defined to have a 5-pin SOT25 package.  The simulation wants the part to have two pins. The "Nodes" parameter maps the local ports of the device to the S-Parameter ports of the simulation.  In the example below, Local Port 2 is mapped to port 1 of the S-Parameters, and Local Port 4 is mapped to port 2 of the S-Parameters.  Ports 1, 3, and 5 are not used, and are therefore set to zero (do not confuse this with ground).  Therefore, the local ports 1 - 5 are mapped as: 0 1 0 2 0.  If one of the simulation ports is to be grounded or left open, the local port must still be mapped to one of the S-Parameter ports, and then in the schematic that port can be grounded or left open.