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