You have a couple of options. 1. Solidworks Flow already has some information loaded in the database for pc boards, although I don't think it is very correct but it is a good starting point. Look in the Flow Simulation | Tools | Engineering Database under Materials | solids | Pre-Defined | Non-isotropic and you will find 3 PCB configurations.
The other method which takes a lot longer is to start calling the local representative for the manufacturer of the raw material that will be used in your pc board. This is not the vendor of the pc board but the manufacturer of the glass resin fiberglass material. You will have to explain what you need the information for as a lot of times they want this information to remain proprietary
As for the add on components, I use Alumina 96% Al2O3 for ceramic chip components like resistors and capacitors. For IC's I use a combination of Epoxy, unfilled die encapsulate for the plastic body and copper for the leads and surface mount pads.
Also remember whenever possible try to test you model against a known result.
I also attached a spreadsheet with the numbers that I use. You can use these at your own risk as I cannot guarantee if they are 100% accurate.
Also, my other main source is www.matweb.com
Hope this gets you started.
Material cross reference.xls 24.0 KB
That will certainly give me a good reference to start with.