Harry Potter and the Word Puzzle of Doom

There is a word game where the starter word is transformed to the ending word by changing one letter at a time. It is known by many names (Doublets, Word-Links, Word Ladder, etc.) and the creation of it is credited to Lewis Carroll. On the plane during a recent trip I challenged myself and my daughter to transform SNAPE to HARRY.
 

Yes, we had recently watched some Harry Potter videos.
 

What I thought would be moderately challenging became a very difficult puzzle. Spoiler: the answer I arrived at is at the end. As I worked my way through, it seemed this process compared well to that of writing in several respects.
 

1. There are rules to follow.


SNAPE
SNAKE
STAKE
STARE
STORE
STORY
SORRY <-- Two letters changed. Not Allowed!

2. Working backwards can lead to discoveries.


HARRY
HARRS <-- Plural of harr, a sea mist or wind from the east.
HERRS <-- Old Norse word for army. Non-english word, Not Allowed!

3. Mastering the rules allows one to bend or break them.


HARRY
LARRY <-- Well, we are going from one proper name to another, right? Also another spelling of lorry.

Below is the full progression that I arrived at. I would love to see other solutions!

SNAPE
SNAKE
STAKE
STARE
STARS
SPARS
SPURS
SOURS
LOURS
LOURY
LORRY
LARRY
HARRY