I've been to Ollalie Lake Campground several times in the last few years. Most recently in Aug 2019. I like that it's quiet and small, with only 5 spots, and limited day use parking. The cost is $12 a space $6 for additional car, and I think it's 1st come, 1st served, but it seems like the forest service is offering reservations via their website lately. I didn't reserve ahead of time, even mid summer I had a choice of a couple spots. There's a clean vault toilet, but no running water, so be sure to bring enough. 

There's trout in the lake for fishing, but I had no luck this time. Boats are allowed, but only hand powered or electric. The lake itself is kinda small, but offers great views of Mt Adams reflecting off the water in the evening. 

The campground was clean, but flies and mosquitos can be overwhelming at times. 

Fresh squeezed tip:

                                   There's a couple free sites just south of the campground entrance that still offer lake access.