Mauville City
Hoenn · Emerald
An X Speed lies on the south edge toward Route 110, 4 tiles west and 5 south of the door to the first house.
Rydel in the Bike Shop hands you an Acro Bike, 1 tile west and 3 north of the door; you can trade it for the Mach Bike.
Rydel in the Bike Shop swaps your Mach Bike for an Acro Bike, 1 tile west and 3 north of the door.
Wattson stands outdoors, 3 tiles west and 5 north of House 1's door, and gives the Basement Key after you beat Norman.
The Coin Case Trader 3 tiles straight north of House 2's door swaps the Coin Case for a Harbor Mail, which the Slateport Poké Mart sells.
The Rock Smash Dude gives you HM06 in the first house, straight north 3 tiles of the door.
Rydel in the Bike Shop hands you a Mach Bike, 1 tile west and 3 north of the door; you can trade it for the Acro Bike.
Rydel in the Bike Shop swaps your Acro Bike for a Mach Bike, 1 tile west and 3 north of the door.
Wattson hands over TM24 once New Mauville is finished; he stands 3 tiles west and 5 north of the first house's door.