There is some discussion at this thread --
http://www.portlandfit.com/forums/index.ph...145&hl=hoodAlso, you can look at how another program explains it at
http://www.teamoregon.com/publications/relays.htmlThe bottom line is this: the best training program for HTC is a good 10K training program. But if you're trying to do both HTC and the marathon, then the main thing is to do your marathon training but to to try running 3 times in a 24 hour period in the last month before HTC.
If you know which legs of HTC you are doing, then you should look at them in advance to find out if they are uphill, downhill, flat, or have rolling hills. But don't get totally attached to the HTC legs you'll run, because it's always possible you'll b assigned to different legs at the last minute.
Practicing with a flashlight is a good idea, too.