The Egin Lakes store and campground are operated separately. Store opens in early April, but sometimes only part time at first. Campground opens in mid-late April, depending on conditions and when the campground host arrives from down south.
There's also two private camps, Idaho Dunes RV and Sand Hills Resort, but I don't have much info on them. Sand Hills is a long way from the west end so you may need to pack additional fuel.
The Egin Lakes host and his wife are good people. They work hard to keep the place cleaned up. We do our part and try not to make their job harder. Have a chat when you see them and let them know you appreciate the work they do. And if it's meal time, invite them in for a plate.
The sand settles quickly to the ground, so just keep a short distance between you and the rider in front and you'll have clean air.
Summer storms roll in fast and furious, then usually depart quickly. We love a storm with some good wind, especially mid-week. Then we go out the next day and ride on smooth sand with few if any other people.