The smaller sites at Juniper Lake are first come first serve, unlike the group sites that can be reserved.  Over the last few years the popularity of Juniper Lake has grown and it is difficult to find a spot on weekends, but early to mid week there's a pretty good chance you can find a spot. If you're lucky enough to get a spot on the lake you'll have one of the most beautiful camping spots in Northern California with an epic view of Mt. Lassen.  There are a couple of good day hikes nearby as well.  Typically camping here is tent camping, but if you have a smaller trailer like a tent trailer or Rpod you might be able to get it in. There are no RV hook ups.