Limited Option Near Lassen NP South Entrance
This is a small flat area near the base of Christie Hill. The turn off of the Hwy 89 is at the McGowan SnoPark area (really just a logger's staging area). There are a handful of very rough roads one could pull off the road and camp in a tent on (or 4x4 van). For a larger RV or travel trailer, we found only one spot (40.390996,-121.540748) that was large enough to accommodate our 32 foot travel trailer. It is right along the road, but there is virtually no traffic here, so we found it acceptable.
I do not believe there are any good spots further down the road. A word of caution as well - the lake just beyond here (McGowan Lake) - is privately owned and gated. It is not available for camping.
Site40.390996, -121.540748
Month of VisitJuly