As for doing this challenge, it's really easy. Panther Within will skip probably 50% of your fights, I.E: Chapter 1 you can skip verse 2 by Panther Jumping the water, same with Chapter 2 and the bridge before the boss (actually, a couple of Shuraba Stingers will get you over when you don't have Panther Within). As for the fights, use items or spam Kilgore glitch if you're desperate to take off time, otherwise sandard combat with Wicked Weaves and some magic-moves will easily reduce your time until you're below threee hours.