I came here for a one night mid-week in summer to spend my birthday.
Note: There are two campgrounds in Beacon Rock State Park. I stayed in the lower RV park and this review is for that.
The campground is set a ways back from main day use area. You go under a railroad bridge to get there. It's a narrow entrance and the only way in and out. There are 5 RV sites with water and electric. There's also bathrooms and shower facilities.
Beacon Rock is a beautiful park, right on the Columbia River not too far from Portland and Vancouver. There's a big huge field and a paved trail around it, a great place to walk your dogs. You can get to the river in several places, including at the boat launch--where there are a few primitive tent sites. The area where the RV sites are is pretty, under some big pines, although there is no privacy between sites. I was the only camper the night I was there.
When I planned to stay here, I knew about the train traffic. I thought it wouldn't bother me, in fact, I thought I would rather enjoy the romantic whistle of the train. What I didn't account for is that the train track was about 10 feet behind my rig and that my whole van would shake each time one went by and rattle me from my sleep. And they went by a lot!
The other thing to consider is the entrance to this campground. I got a little paranoid in the middle of the night--probably train noise-induced anxiety--that someone would come in the night and block the narrow entrance and trap me inside. Probably not something most people will worry about, but as a solo camper, I felt a little vulnerable.