The most authoritative and complete English translation of the Inner Chapters (the esoteric, Taoist alchemy section) is:
Step 1: Start with Chapter 1 (Zhenxian – "True Immortals") Ware’s translation opens with Ge Hong arguing that immortality is real. He uses logic and historical examples. This sets the tone. baopuzi english translation pdf best
via his official site, The Golden Elixir, which are excellent for understanding the alchemical terminology. Key Themes in the Piece (PDF) Seeking Immortality in Ge Hong's Baopuzi neipian The Golden Elixir
2. The Scholar's Choice: Feifel's "Pao-p'u tzu" (Monumenta Serica, 1941–46) baopuzi english translation pdf best