The campground at Potholes State Park seems very well taken care of despite the older bathroom/shower facilities. We enjoyed our short stay and would stay again. We stayed in mid-August and the Potholes State Park weather was very hot (low 100s). Coupled with the no swim guidelines (due to algae) made for a very uncomfortable stay. Things did cool off overnight which made sleeping bearable. We were able to make Potholes State Park reservations online a few days before our arrival. In mid-August there were plenty of sites available in all loops. If you are unable to make online reservations you can pay when you arrive if there are available sites.
Boating is the major attraction at Potholes State Park. There is a single trail that follows the river for about 1/2 mile. The campground and picnic area are very large and make for a nice walking area. The picnic area has tables and grills (though you will want to check the current fire bans). It also has a huge area of grass where you could setup games to keep entertained. The private showers lacked any way to hang your belongings, so bring some way to hang them off the door.
The park is named after the "Potholes" that formed around this area of eastern Washington. Lava covered the area before the last Ice Age. Ice, wind, water, and sand wore away the lava fields in scattered spots. This wearing produced depressions which later filled with water. These water filled depressions give the appearance of "potholes".
Potholes State Park camping is available in three different loops.
In all loops there are large trees that provide some shade. Since the trees are tall and narrow they don't provide a lot of shade per tree but there are a lot of trees in rows.
The first loop consists of full hookup sites. The sites are gravel and fairly level. There is decent space at each site and we saw several large rigs. This full hookup loop has bathrooms and showers. The grounds around the loop are very well taken care of. The other two loops are dry camping sites. They are decently spread out but weren't very level and were pretty dusty. One of the two loops is close to the river and the other is close to the lake. The one nearest the lake has a short walk to the showers and flush toilets. If you don't have your own rig or tent Potholes State Park cabins are available in each dry camping loop. They looked cute from the outside and we could see AC units in the walls.
There are two sets of flush toilets and showers. One is in the full hookups loop and the other is near the picnic / boat launch area. The buildings and fixtures were pretty worn out but clean and functional. Showers were free and had hot water, but were extremely humid due to a lack of ventilation. Numerous flying bugs lived in buildings when we visited in the summer but didn't present much of a problem. Interestingly the there were single private showers and bathrooms in one building and shower and toilet stalls in another. We prefer the private type. Away from the main park area there were several pit toilets. We also found water spigots scattered through the dry camping loops. The dump station had 2 lanes and rinse water. The dump station fresh water fill was located far enough from the dump for us to feel comfortable using it.
Since we don't have a boat we can't comment on the major attraction of this park. We did notice several places that rent boats and jet skis close to the park.
If you plan to spend time here and won't be boating or fishing you'll need to bring things to do. You can use the large grassy picnic area to setup games - even games like volleyball or soccer that take a big area. There is a lot of space in the park for kids to play both at the picnic area as well as the full hookup loop. The dry loops have less open space without trees and tends to be dustier.
There is a short trail along the river. The trail is flat and a bit sandy.
The city of Moses Lake has Walmart, Home Depot, Lowe's, fast food, gas, etc. You should be able to find any common items you need here.
We were able to take nice sunset pictures over the lake, but didn't find much else to do in the area.