The Master Cleanse is a very good fast, during which you will not feel hungry, and in fact will feel quite energized.
A very powerful prayer is the Meditation Twin Hearts by Master Choa Kok Sui. You can find that meditation in the book entitled "Your Hands Can Heal You" by Co and Robins.
Best of luck to you in preparing for the retreat. It takes a very advanced soul to realize that preparation before meeting with someone like Master Lin will add greatly to the experience.
