Having finished the tutorial, you must now search for the men who tried to kill you. Based on what you hear at Goodsprings, they have went to Primm, and took the long route around.
Head to Primm, which is southeast of Goodsprings. Upon arriving, an NCR trooper will tell you that Primm has been overrun by convicts. Ignore his warning and enter the town. There are approximately six convicts, and you must kill them all to liberate the town. Once you do so, enter the Vikki and Vance casino and talk to Johnson Nash. He'll tell you to head to Nipton.
If desired, you can examine other conversation options to obtain the My Kind of Town quest, where you need to rescue deputy beagle inside the nearby hotel.
Follow the road south of Primm and then go east. Upon arrival, you'll find that everything's been burned to the ground. You'll find a group of Legion soldiers led by a man named Vulpes Inculta, who provies the quest Cold, Cold Heart. You can then find a man named Boxcars inside a store, who will tell you to go to Novac, and possibly open the quest Booted.
Follow the highway out of Nipton and head north to find Novac. This part of the quest is dangerous, since there are a few viper gunslingers watching a wreckage with a grenade rifles. You can take out one viper by sneaking around from the south, and throwing explosives. Otherwise, you may have to take a detour.
Once at Novac, you have several options to proceed:
- Talk to Manny Vargas (located in the T-rex mouth during the daytime) and complete the quest Come Fly With Me to get him to help you.
- Talk to Manny Vargas and use the Confirmed Bachelor perk to get him to tell you where to go.
- Read Manny's journal logs on his terminal in his hotel room to find out where to go.
Take the road north out of Novac and make your way to Boulder City. Once there, talk to Lieutenant Monroe to start the quest Boulder City Showdown. This side quest is completed by resolving the hostage situation.
To complete the main quest, the only requirement is to speak with Jessup or to collect the engraved lighter from him.