Thanks for the kind words, JT -- that is exactly why we have a blog -- to help take us back to those places, especially when (as now) I am stuck in town because of work. (I like my work, but I also like to travel!) Camping season will soon be here again . . . .
Returning to the OP's question about Lassen, be sure to bring either a telephoto lens or a small pair of binoculars to the Bumpass area -- you can get some great close-ups of the boiling mud pots:
Take your time on that trail -- it is at around 8000 feet, and pretty steep. Bring water, of course. It is very worthwhile -- the volcanic area is not only scenic, it comes complete with sound effects (roaring steam vents) and even "smell effects" (sulfur gas).