First off I wanted to show off the background. I put in a ton of effort into this... There's even a health department letter grade on the doors, bricks on the walls and blinds in the windows.
John is describing the world tour where him and George went around the world looking for answers about George potentially not having his soul. It's not every step that they went through, but the ones that John felt he was risking his life on. Here's links to each of them that he mentions:
The serial killer
Then the boat sank
We got swallowed by a whale
only to be rescued by a ghost ship
The French revolution
The Swiss guards at the Vatican
Trapped in a maze with a minotaur
Mummy court
Acts of God
The infection I got swimming in the Ganges river
Frostbite in the Himalayas
The blind, bunny vampires
The prison riot
Kaiju making sweet, sweet love to our airplane
The plane crash
Giant monkey turds
Alien abduction-- not to mention the anal probing
Nazi treasure hunters and booby traps
And the crazy, doll cult
Also, the reason George sold his soul to Hell
was to save Zoey from becoming a zombie.