Hwy 3 > Cross the 1 lane bridge called "South Bull Run Rd" > continue to the right past a few houses until you reach Coeur d'alene Trail access parking area > cross over trail and continue down parallel West Bull Run rd
4 spots that I found. One is a large loop with fire pits already setup (where I stayed). There's one back-in that used to be a 2 track trail next to a small pond, another pull-through loop next to the main sign, and one more site down the road towards the forest.
You're really close to highway 3 so there's road noise from that. More common actually was the sound of boats going down the Coeur d'Alene river which is even closer. There's another camping area across the river (which is apparently contaminated with toxic materials from mining lol). I was here during 4th of July so people were lighting off fire crackers there as you'd expect.
Overall it's a very beautiful spot, with multiple small lakes, deer grazing around, and plenty of wildflowers.
Had no issue with my 25ft trailer as the road was in good shape. Larger rigs would probably be okay too, but I'd scout it out.
This is Idaho Fish and Wildlife property and has a 3-day maximum stay.