Campfire Warp to the 'A' on the map and you'll be outside your home with your wife and son! Once the emotional cut-scene is over and the mission starts proper, get your horse and pick up your son by the barn.
Ride until you meet up with a familiar face and you keep your promise of buying some of the MacFarlane's cattle. Meet up with Bonnie and go to the back of the herd, move the herd out of the pen towards the destination indicated as a yellow dot on your map.
As per usual, a few of the cattle will have other ideas and will try and wander off, so keep your eyes peeled at all times so you can quickly guide them back to the herd. Press onwards until you come across a band of rustlers, which require you to fill 'em full of lead before they can steal any of your cattle.
You'll need to fend off two groups of rustlers before you can proceed onwards with Jack until you reach home, where you need to encourage your herd into the pen and then tie up your horse to complete the mission.