safe bet is 1 1/2 to 2 hours. Depends how long your nav legs are really.
Good Luck, plan and prepare well have it clear in your mind what you are doing and dont be afraid or hesitant in making decisions and changing the plan, be authoritive and show your ability to command, you will be fine.
Good Luck i am rooting for you.
Where are you taking the test? I might be able to help you a little more if it is the area i used to fly.