Mikasa - welcome to the group. There is a wealth of experience and knowledge here and I'm sure any questions will be answered. I used to rely on carbs for fuel but I changed to LCHF last November and I will never go back.. It took a bit to get my head around the whole fat is good idea but the benifits are so worth it..
SS - have you considered a camelbak or something similar rather than carrying a bottle? I found using 1 double sachet with 700ml of water worked because 500ml mate it too sweet.
Shades - I don't know why but my legs seem to really tighten up very quickly. Every time I go get a massage the guy can't believe how right my legs get and he spends an hour just getting the knots out. It might be because of my job.. I like the idea of a spreadsheet cause I've started filling my calendar up already ams I don't want to forget I've booked a race..