Back in the Saddle

 is a tutorial quest in Fallout: New Vegas.

Quick walkthrough

 * 1) Talk to Sunny Smiles at the Prospector Saloon.
 * 2) Follow her outside and shoot three empty bottles. She will provide you with a varmint rifle and ammo.
 * 3) Continue on with Sunny or end the tutorial.
 * 4) Accompany Sunny to Goodsprings Source, clearing three wells of geckos along the way.
 * 5) Talk to Sunny for 50 XP and 50 bottle caps.

Detailed walkthrough
After setting up your character via the small tutorial inside Doc Mitchell's house, he will direct you to the Prospector Saloon, stating that a woman named Sunny Smiles will be able to help you with your dilemma. When you enter, you will be greeted by Cheyenne, Sunny's dog, and Sunny herself. She tells you that the Doc informed her of your coming and to meet her out back. Follow her, and upon reaching her outside, she will give you a varmint rifle and 30 5.56 round. A shooting tutorial ensues, teaching you about aiming down the sights and crouching. After you shoot the 3 Sunset Sarsaparilla bottles, she will then ask you if you would like to tag along on a little job. At this point, any time you talk to her you can choose to end the tutorial, but this will forfeit several rewards.

You'll receive 60 5.56mm rounds upon agreeing to help and then run south east, towards the Goodsprings Source. Once you get close to the first well, Sunny will tell you to sneak, by crouching, to surprise the geckos. Once the geckos are dead, speak to Sunny and continue on to the next two wells. There should be three geckos at the next well, and three geckos attacking a Goodsprings settler near the final well. Kill the geckos and talk to the Goodsprings settler; she will give you 3 bottles of purified water and improves your reputation in Goodsprings. If the Goodsprings settler dies, you won't receive the reputation boost or the purified water, but can loot her body for a cleaver, field hand outfit and a handful of caps. Talk to Sunny afterwards to receive 50 XP, get paid 50 caps and have the opportunity to start By a Campfire on the Trail (and lament the settler's death in dialog, if appropriate).

Behind the scenes
The title of the quest is a reference to the song "Back in the Saddle Again" by Gene Autry.

Bugs

 * There is a bug that may happen if you finish the tutorial after the shooting lesson, and then fail the quests Run Goodsprings Run and Ghost Town Gunfight before you talk to Trudy, the option that ends the quest may not work and the quest may never end.
 * It is possible for the mission to not continue automatically. if a random critter appears outside the saloon when you follow Sunny and she moves to attack she will not give you the rifle or the mission unless you push her back to where she was standing when you come out of the saloon.
 * If you already own the varmint rifle she gives you, you may auto equip the one you already have instead of receiving a new one.
 * It is highly unlikely that Sunny Smiles will spawn in Hidden Valley. There is no work around but to go and meet her in Hidden Valley and as soon as you do go and meet her and enter VATs the game will freeze. (Leaving before her in the saloon, waiting behind the bar could trigger this) Cheyenne will just casually wait outside, but Sunny will never show up. This is very annoying and is a possible game-breaker if you want to side with the Powder Gangers.
 * Sometimes the distressed settler will not talk to you after saving her and she will just back away towards goodsprings, knife drawn and crouching.