Lots of campgrounds to choose from. Some are dustier than others. Plenty of space between campsites. Fire pits available for use but check for burn bans.
This place is where I go when I want to disconnect and get away from the stress of school in Ellensburg. I've been here a handful of times and there's never been more than a dozen people spread out over the entire coulee valley. The previous directions are good and the one on WTA will take you right to the parking lot where it's an easy 1.5 mile hike down into the coulee. I've heard other people say they walked in from ancient lakes road and it took three times as long to make it to the camping spots.
The lakes are safe for swimming in my opinion (there's even a rock to jump off on the closest lake!) But do carry your own water in, it is irrigation runoff and has plenty of yummy pesticides that you cannot filter out. Other than that enjoy the lakes, waterfalls and killer sunsets that happen on a nightly basis out here!
This is a good early season hike while its still rainy in Seattle it can easily be sunny and warm on the other side of the mountains. There are at least 5 good campsites at the lakes that will each hold multiple tents no problem. Some people do light fires but I’d like to discourage it, fire danger is pretty real in these scrublands. This is a very pretty hike full of sage brush and interesting geological features, also several waterfalls. Past the lakes you can go out to the Columbia River Gorge. Check out the WTA description for more details. Note that there is no potable water, you have to haul it it. The lakes are contaminated by irrigation run off.
2 mile backpack into box canyon and 2 night campout. Surrounded on three sides by tall basalt column cliff walls. Small water fall at northeastern corner. Incredible hiking up to top of rim and around to secondary canyon with a larger lake. You can also hike down towards the Columbia river where there is some additional camping available. Go in early spring for the green and cooler temps. You will want to bring a sleeping pad and tarp since ground is rough. Make sure you bring your own water! Even though there are lakes in the canyon, none of the water is safe for drinking due to the agricultural run off. Filtering will not work.