Hi, I did this trip in November and it was amazing. It was my first solo trip and I was nervous, but I can honestly say my anxieties were over the minute I got on the coach.
it was very full on, with early starts and full days but they were worth it all. There was a lot of catch journies but it was wonderful watching the world go by and seeing, the villages and day to day life.
Embrace every minute and enjoy.
You will live out of a suitcase so use plenty of packing cubes.You can get laundry done at hotels with 2 night stays so don't overpack.
take wet wipes and hand sanitizer , especially for the trains.
don't worry about shampoos, toothpaste and shower gels, they are all in the hotel rooms x