Head to the rocks above the construction crews warning zone, right side of screen. Go to Neil's Shack, act nice to him. Once your conversation is concluded, keep going that way. You'll be attacked by supermutants later, but if you have a service rifle, you can kill them and loot their bodies. Neil will not attack you.

Keep the flame weapon you loot off the body(s). Head towards New Vegas until the rocks end. You will see New Vegas buildings. Wait until daylight, the Deathcklaws won't attack that sector, evidently because both local gangs and the NCR army cooperate to keep it Deathclaw free.
Save and continue.

Or take a different route

Going straight through gets you there faster. It just saves time.

Or...you could follow the path the game lays out.

The intention isn't that you sneak past the deathclaws and other baddies up north it's to passively direct you South into following Benny's trail.

I have figured out that if you go to the Hidden Vally Bunker there are two holes in the fence on the eastern side. If you take the first one it will take you the Scorpion Gultch. The gultch is than a straight shot to Helios and Novac and all you have to do is follow the road north to Vegas!

The gultch is full of scorpions so if you're low level than I'd advise just hauling ass straight through it.

Don't take the second hole. It goes to Black Mountain.

Its sandbox the point is to do whatever the hell we want!, Even if you follow the path the game lays out, you still have to get to New Vegas alive. Not a walk in the park at low level.