Running

Traditionally, you go for distance, however, IMO, that doesn't represent the stress of a fight. Sprinting is much closer, but it's harder to keep up that pace obviously. Interval sprints can be a lot of fun - 2:30 of jogging or fast-paced, 30 sec. sprinting. 1 minute rest. Repeat for however many rounds you think you'll need. Personally, I try not to run as my knees aren't in the best condition and I try to go on the beach whenever possible. Circuit training in the gym can also work.

Stay off the treadmill! Do your roadwork on the road! Treadmills don't work your hammies at all, since you're letting the belt pull your legs back. You'll definitely notice a difference if you work on the road.

You can make it more realistic if you run on an incline. Jack the treadmill up - recommend incline of 2.5 or more (on most machines).

Elliptical machine is better, but still not as good as the actual road. Check out Enamait's book Infinite Intensity for some excellent conditioning ideas: http://www.whywenothithard.com/2007/10/review-inifinite-intensity.html