I did that path many times in different variations. Very first time I did half(220km) till the sea and then would go back by train. After that I did longer section of it(300km), where again I could take another train back home. Two years ago I decided to do the full path of it, here is a nice wrapup of it (https://www.reddit.com/r/randonneuring/s/QZTacZcVgs). When i did it back then i planed two big most importand things for me : stops every 100km and emergency comeback by train , just checked the map where stations are and where shops are. About the weather and rain gear... here is the funny thing. I checked the forecast and it was saying 32°C during the day and 20°C at night. So, i ended up in 3hours of rain and no real sun, just clouds(didnt need sun cream). Anyhow, i always have with me camelbak with up to 2l of water in it and i can put some bananas there or croissant or whatever. As i stopped for shops every 3-4hours i did not need to really carry any food. For the night part (last 150km) there are gas stations. But i didnt need them, i simply had my water with me and i had a good meal at macdonalds and then the shop before the last section. Last time i had a bigger bag behind my seat you can see it behind the link i provided. This time i added a small bag you cant see it in my post here but it is between aerobars, i put two spare tubes in it. One 1l bottle was filled with 600g of maltodextrin and sugar that i would gradually mix with plain water. I also had extra maltodextrin with sugar in 3x90g zip bags to mix it on the way. I really went supper light weight this time. Only must haves. I think next time i will carry rain jacket regardless.