Food that I carry is Frusli bars (cheaper than the ‘special’ energy bars) and I use PSP to drink, but I use the unflavoured as it is cheaper and you can flavour it yourself with squash if you want. I keep a few power gels in case of need. I also ate quite a lot of cake on my end to end!
The GPX files for my All SEWN up #lejog is at: https://sites.google.com/site/gregcycle/gpx-files-for-the-all-sewn-up-tour
9 The Start/Finish
Websites include http://www.raintoday.co.uk/ for where the rain is now and an indication of where it is going, and for wind see http://www.xcweather.co.uk/
Well I hope that has helped, I don’t know what your knowledge level or experience is, so sorry if you have found it patronising. I do believe you can do it if you want to. Do remember to enjoy it on the way, and anything hard or difficult is just part of the experience. My view was short of total mechanical failure of the bike or me I was going to get there.
Good luck, take care and stay alive, play nicely with the cars and most of all enjoy.