Not only that, but I believe they killed my brother, and I'm going to hunt them down and break up their gang or die in the attempt.

There's your plot.

It needn't be overdone in the least, to have thrills enough.
And there would be all kinds of chance for real range-stuff, like the handling of cattle and all that.
"We can use this ranch just as it is, and have the outlaws down next the river.

I'm glad you haven't taken any scenes that show the ranch as a whole.

You've stuck to your close-up, great-heaven scenes so much," she went on with merciless frankness, "that you've really not cheapened the place by showing more than a little bit at a time.
"You might start by making Lee up for my brother, and kill him in the first reel; show the outlaws when they shoot him and run off with a bunch of stock they're after.