Here is the full list of all 25 Totally Reliable Delivery Service achievements.
Bring the conch shell to top of mountain.
Put treasure chest on sloop.
Bring grill to Dad Statue in Golden Ruins.
Bring the luchador mask to wrestling ring.
Return the satellite to GASA.
Pass gas in a biplane.
Bring banana to room 5 at Banana Motel.
Bring foam hand to Booster Club Arena.
Find the big secret bear.
Complete 100 different deliveries.
Complete 50 different deliveries.
Lose pants in tornado at Happy Clam Resort.
Visit Keister Island.
Visit Gasa Research Facility.
Find the tiny island.
Unlock the rocket booster.
Unlock the pickup truck.
Visit Happy Clam Resort.
Unlock the helicopter.
Complete 10 different deliveries.
Unlock the buggy.
Unlock the mule.
Remain airborne for 10 seconds.
Complete first delivery.
Change your clothes.