Fallout: New Vegas Walkthrough - Can You Find It in Your Heart?
The NCR needs a little help. Ranger Jackson at the Mojave Outpost needs some help clearing out the caravan passages to secure the supply lines. This translates into getting paid some good gear to kill a bunch of big ants.
Mojave Outpost - Helping Ranger Jackson
Ranger Jackson needs a little bit of help. You can find him by walking into the back of the Mojave Outpost Command Center. Major Knight can direct you to him too.
Talk to Ranger Jackson to learn that he could use some help killing a bunch of ants. You can get some surplus supplies for clearing the caravan road, so it's a good deal. Make sure that you go out with a rifle and a shotgun. There are a lot of ants and you'll want some options if they manage to swarm you.
Can You Find It in Your Heart? - Killing the Ants
Walk over to the marked location. It's an underpass close to the Nipton Rest Stop. If you didn't go to the actual rest stop before, watch out for some radscorpions that might be there. It's not going to be fun if you get attacked from both sides, so make sure that you're clear before you start hunting.
The best way to do this is to put your back to the rest stop and look down into the mass of ants. Use a good rifle to dish out a bunch of damage while they try to climb out of the pit to attack you. If you can, focus on one side. If you stick to the edges, you may not trigger all of the giant ants at once. Pick away at them as they climb up, then switch to a shotgun (or use the rifle in VATS) to blow them away when they get close. It actually shouldn't be too hard to walk away without a scratch if you have a half decent weapon.
If worse comes to worse, remember that you can fall back to the gas station and use the wreckage for a height advantage. You can also try to hit their antennae to send them into a frenzy.
It doesn't really matter how you do this. As soon as the giant ants are dead, you can loot their bodies for some ant meat and ant nectar. when you go back to Ranger Jackson, he'll reward you with some "lost" supplies. It's actually a very good reward. You should get a few Caravan lucnhes (which are great healing items), some medicine, a service rifle (which is a great update in the early game) and a few caps.
Note that this is also helpful for a few other quests. It doesn't hurt to have Ranger Jackson on your side when it's time to help Cass. The quest for Primm's sheriff is also a bit easier. If you've helped out Mojave Outpost, then Major Knight will be able to send NCR reinforcements to Primm without the Barter check. If you want to support the NCR, this is a good way to build up your reputation.