Hi,
Whenever you create a new solution using your guidance package, it will use your guidance package dll. You can get the assembly path using reflection. Now, this path is where your guidance package items are installed. From here, you have your folders @"Templates\Solutions\Projects".
You can combine both your assembly path + @"Templates\Solutions\Projects", which will give you the projects path, where your projects reside.
I hope this answers your question.
Regards,
-Noor.