Simulation models for the cable and PCB can be generated by either measurement or simulation. If you have the cable, measure the s-parameters of the cable using a VNA and save it in touchstone format such that you have a .S2P file to use in your simulations. If you don't have the cable you need to find out what type of cable you will be using because they have different characteristics, for example some cables come with equalizing properties. Some of the cable manufactures will provide s-parameter models for their cables on their websites or you can request them.
For PCB, you need to find out what type of material, such as FR4, Rodgers 6xxx, etc. If you have the PCB already you can measure s-parameters using a VNA or there are some software that will generate a spice netlist when you do a TDR of the PCB line using a oscilloscope. If you don't have the PCB, then a s-parameter or spice model can be generated using an EM simulator such as ADS, Sonnet, Q3D(Ansoft). The important properties to model are skin effect and dielectric loss of the PCB.