My advise for prep is to get as fit as possible, plan exhaustively as to a realistic number of miles you feel able to accomplish on a daily basis. Start off modestly and build up as you get fitter.
Check out your route on Google Earth, masses of info there in conjunction with ACA maps.
Spend your money on having your wheels built and best quality tyres. I have my wheels built crossing the spokes over 4 times, gives me extra strength to take my weight 90kg and pack. Actually loads of good info on this forum, but like mine everyone has their own view on kit. Which is why cycling is always so interesting.
In the end just go for it and enjoy = good luck.
My site is www.bike4gus.com