Honestly, for me thats not much distance, but i understand it might be different for you. Your best bet is to run long distances and run terrain that will be similar to your marathons . Considering your in tx, the weather shouldn't be too shabby for you. 3 and 6 mile runs will not make your body do weird things so you should have to worry about carb loading up or anything. I wouldn't recommend downing energy drinks or anything of that nature, just hydrate the night prior and in the morning with water. After wards, it wouldnt hurt to down a Gatorade for faster recovery. Make sure you stretch very good up to the events to ensure you won't cramp or injure urself. Thats about it, besides that, its all mental.
Zetec Crew #152
United States Army