Dust to Dust - Prairie Outpost
First Available: Chapter 2
Other Requirements: Complete Gone Hunting & Reach Chapter 2
Location: Prairie Outpost
Rewards: 600 EXP & 5 Mega Potions
You'll find Dave at the Prairie Outpost after completing the Gone Hunting side quest from him. Dave is one of the side quest NPCs that "follows" you throughout the entire game, typically appearing at the rest stops you visit along your way. All of his side quests are straight forward, you typically go to an area and fight a few monsters before collecting the Dog Tag.
The Dog Tag you need to collect is found on the driver's seat of a beat up old buggy in the center of the quest location on the map. There is a tree with Leidan Peppers right next to it that you'll want to gather while you're here. Once you've collected the Dog Tag you're free to return to Dave and turn it in.
Completion of this side quest will unlock the next one, Final Resting Plains. You'll be able to pick this quest up at the start of Chapter 3 from Dave at the Coernix Rest Station.