Yikes

So I got my training plan for the Avon Walk for Breast Cancer. I am a little nervous, it is quite daunting. 24 weeks, 7 days a week. Now that I have had a couple of days to digest everything I think it will work out okay. There are 3 days a week where I will be doing cross training (yoga, swimming, cycling, etc) to break up the walking and then one day to recoup (just a 15 min walk). I think as long as I stick to the plan I will do just great. I should be in really good shape once this is done (at least I am hoping that is the case). I am currently researching different diets. I know I am going to need to increase my protein and cut back on sweets. But I need to figure out what to do about the carbs-I would think I would need some. I always hear about runners doing a spaghetti dinner before their races (we used to do this before swim meets as well). Anyone have any suggestions? Any help would be much appreciated.
Here is the link to show what I am going to be doing for the next 6mos or so. (I have decided to start within the next week or so to try and get a head start on things, I need all the training I can get).
http://info.avonfoundation.org/site/DocServer/AvonTrain_39mi_24wk.pdf?docID=5909