Rewards:
After completing Free Larry, he’ll give you this mission immediately while talking to him. The next objective will require you to destroy the radio/satellite dishes at the top of the Purpletop Telecom Tower. While you should be able to climb it using your grappling hook. However, if you happen to own a weaponized helicopter like the Kaumbat H-04B Firefly. There’s a helicopter shop down the road east of US Auto outpost or north of the lab that you can fast-travel to.
After securing your chopper, fly to the tower and take out the cultists guarding the base of the tower. Next, find the marked targets and destroy all of them. Larry will arrive later with his own chopper and you’ll be required to fly with him next. If you’re on your own chopper, you have to ditch and grapple under Larry’s chopper and climb up to the cockpit. If you can't get to Larry's chopper in time, the mission will fail but once the checkpoint reloads, you'll already be hanging under the helicopter so you just need to climb up.
Larry will fly back to his lab. However, there are peggies waiting in the compound. You can deal with them however you like it. The mission will be complete once all enemies in the area have been killed.