Hey, cool goals you have there. I am into running, and the only thing I can think of to encourage you on your way to a 30 min 5k goal is to run those 5k's! You are looking at a 10 min/mile pace, which is totally doable in a 6 week challenge, so this was a most excellent choice. The run/walk method is really effective. Set your goal pace for either 2:30 quarter miles or 6 minute kilometers. I don't know how you are measuring your pace distance. Anyway, run at the pace you need to succeed in your goal for as far as you can, then walk when you get to tired to run. After a good 5 minutes or so of walking you should feel recharged enough to run some more. Just keep moving until you get to the 5k mark, and after some practice you will be able to keep your goal pace. So that's all the advice I have for you, good luck! Also, I am going to try that cold yogurt idea, it sounds most interesting.