Regards Fly-Dad
Whilst Henry is correct, you can however file for a random route after the tracks expire.
On saying this, you should expect a re-route or change in flight levels from that filed.
All the questions that you have asked (including your FMS time questions in another post) are covered in FlightSafety's International Procedures initial and recurrent training, with a very good manual for reference provided also!
I hope that this helps.
(P.S are you arranging for your own clearance's or using a third party such as Universal Wx or Jepp?)
500 Above (but not on the tracks hopefully!)