Buy order:
TM07, Super Potion, Super Repel, Poke Doll, TM48, Fresh Water, 

Route Fly (2 swaps, 30 scrolls, 3 Pokemon scrolls):
Swap slot 2 for Super Repel
Teach TM48 to Nidoking over Horn Attack
Use Super Repel
Swap slot 3 for X Accuracy
Teach HM02 to Pidgey/Spearow

New Fly (1 swap, 27 scrolls, 5 Pokemon scrolls):
Swap slot 5 for X Speed
Teach HM02 to Pidgey/Spearow
Use Super Repel
Teach TM48 to Nidoking over Horn Attack

Route: 2/30/3
New: 1/27/5

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Route Pre-Marowak (9 scrolls):
Teach TM07 to Nidoking over Rock Slide

New Pre-Marowak (1 swap, 13 scrolls):
Swap slot 2 for Super Repel
Teach TM07 to Nidoking over Rock Slide

Route: 2/39/3
New: 2/40/5

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Route Marowak (11 scrolls):
Use Poke Doll

New Marowak (1 swap, 15 scrolls):
Swap slot 3 for X Accuracy
Use Poke Doll

Route: 2/50/3
New: 3/55/5

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Route Silph Rival (13 scrolls):
X Speeds are in slot 14

My Silph Rival (4 scrolls):
X Speeds are in slot 5

Route: 2/63/3
New: 3/59/5

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Route Snorlax (1 swap, 16 scrolls):
Swap slot 5 for X Speed
Use Poke Flute

New Snorlax (16 scrolls):
Use Poke Flute

Route: 3/79/3
New: 3/75/5