I don't know the area around Estes Park.  But I'll offer this as a primer for camping in the west. A lot of the west is very different than riding in the east.  Western states have a lot of public land, So camping is dispearsed or primative.  It's hard for private horses camps to make money when they compete with free camping. So we don't have a lot of private horses camps that advertize their availability. What you do see are more of the Dude Ranches that offer full sevices.  their horses, cooked meals, herding their cows etc. Just look in the back of any of the Trail Riding magazines,  Lots of horse camps in other states. But states like Utah have almost None.

For those just wanting to do their own thing. We usually just pull off the road and dispease camp in the trees.  In High Use areas, especially around National Parks, The Forest Service will often restrict where you can do dispeared camping. But a phone call or checking with the rangers will point you to areas where you can camp in the forest.

Most of the offical Forest Service Camp Ground, are geared toward  RVs, 5th Wheels, maybe even the occassional tenter. So they frown upon horses in the camp grounds leaving road apples around picnic tables etc. so these camp grounds almost always exclude horses.

So we just pull off in the trees.

From Memorial Day Weekend near Bryce Canyon National Park

Horses highlined

Near Yellowstone National Park last summer