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