A few weeks ago I was up at Lassen. I ended up stopping into the Forest Service info office just north of the park. I admitted I am a rock geek, and they whipped out this self-guided roadside geology tour of the medicine lake highlands. It was great! I finally looked it up online, and it turns out they have tons of these sorts of things. I never knew that, so I thought maybe some other people might find them of interest:

Shasta-Trinity National Forest
www.fs.fed.us/r5/shastatr...-index.shtml

Lassen National Forest
www.fs.fed.us/r5/lassen/maps/
(not as many)

My one caveat was that their handouts made some roads appear bigger than they really were, and some of the mileage was off. But still cool!

BTW, I had been up to lassen at least half a dozen times in recent years, but this was the first time I went to the subway cave (forest, not park) and the hat creek valley roadside overlook. I strongly recommend both as side diversions if you are on your way from the main park road to/from the Butte Lake area -- the cave is a 1/3 mile lava tube you can walk through. The overlook provides this amazing view of the cascades from Brokeoff & Lassen to Shasta and beyond.

Cian