Belly of the Beast

Belly of the Beast is a main quest in Fallout 76.

Quick walkthrough

 * Use four Brotherhood emergency transponder radios to find Elizabeth Taggerdy's location. Game doesn't checkpoint radio progress, so if logged out, likely will have to start over to maintain radio progress until get inside cavern for location guide to Taggerdy (large cavern).
 * Head to and enter the glassed cavern
 * Make your way through the caverns towards the last transponder radio
 * Kill the Scorchbeast blocking you from the last transponder, if necessary
 * Use the last transponder next to Taggerdy's body
 * Pick up Lieutenant Elizabeth Taggerdy's ID from her corpse so that you can access the information on her terminal and also use it to access the elevator outside the Asylum if you don't have your own military ID.
 * Get out of the Caverns and head back to Fort Defiance. There is an exit near Taggerdy to leave the caverns if necessary
 * Use Taggerdy's terminal to learn more about the Scorched, Scorchbeasts, and ultracite power armor

Detailed walkthrough
This quest consists of four beacons that must be located in sequence before ultimately leading you to the glassed cavern. See the gallery for map locations and screenshots.

Beacon 1 is located on the road between Fort Defiance and Watoga. Be prepared to battle Scorched, mirelurks, cave crickets, robots, or some combination thereof. Approach and interact with the transponder relay to listen and acquire coordinates of the next Beacon.

Beacon 2 is located in Watoga, by the crashed vertibot in front of AMS corporate headquarters. Be prepared to battle robots and Scorched. Approach and interact with the transponder relay to listen and acquire coordinates of the next Beacon.

Beacon 3 is located at Survey camp Alpha which is East-SouthEast from Watoga Station. Be prepared to battle Scorched and a Scorchbeast. You may need to repair the Surface to Air Missle battery that will attack the Scorchbeast and the Scorched. You may need to repair it several times before the Scorchbeast is killed. There is a Power Armor Station at this location to scrap any junk and repair your Power Armor. Be sure to look around for loot. Approach and interact with the transponder relay to listen and acquire coordinates of the next Beacon.

Beacon 4 is located at Drop site V9 which is North-Northeast of the Fissure site Prime. The Beacon is located on top of the bunker. Be prepared to battle many Scorched. I used stealth boy while near the Fissure Prime to avoid being attacked by any Scorchbeast. Approach and interact with the transponder relay to listen and acquire coordinates of the next Beacon at the Glassed Cavern.