Activate Scaretiller by tapping it, targeting Cacophodon.
Scaretiller triggers, returning Riveteers Overlook from your graveyard to the battlefield tapped.
Riveteers Overlook enters the battlefield, triggering itself and Roaring Earth.
Resolve the Roaring Earth trigger, putting a +1/+1 counter on Cacophodon.
Resolve the Riveteers Overlook trigger, causing you to sacrifice it and search your library for a basic Mountain, Swamp or Forest and put it onto the battlefield tapped.
If you put a land onto the battlefield this way, Roaring Earth triggers, putting a +1/+1 counter on a creature you control.
Resolve the Scaretiller ability from step 1, dealing 1 damage to Cacophodon.
Cacophodon triggers, untapping Scaretiller.
Repeat.
Results
Infinite +1/+1 counters on Cacophodon.
Infinite landfall triggers.
Put all basic Swamps, Forests, and Mountains from your library onto the battlefield.