Troop has gone to Lassen many times. Mostly for the Bizz Johnson bike trip. There is a 25 mile trail for biking that can go even longer that has been enjoyed by the troop for biking. The Troop biked into the nearby town for Pizza. Mr Wilson also reports that Lassen is great for fishing. We often stayed at the Goumaz campsite which is free but a First come first serve site. People have reserved a site at Hat Creek Campground info: https://www.fs.usda.gov/recarea/lassen/recarea/?recid=11425 if they don't want to deal with the stress of trying to make first come first serve. The Hat Creek site cost $16 and there are so many sites that the likelihood of being full is very low.
Information website: https://www.nps.gov/lavo/planyourvisit/camping-in-campgrounds.htm
Map Link (beta): https://www.google.com/maps?q=40.4481503,-121.0288829
Bookings: