I did this when I was about 8 on the first family camping trip in the custom VW camper my dad still has almost 25 years later. I remeber my first experience of pain from hiking being the soreness in my calves the next day after the struggle up the loose cinders. From what I read from the others postings, I'll be sure to revisit.
Hiked up this during one of my early tours de Lassen, with Rachel, whilst doing a Snag Lake-Butte Lake loop. Amazing area- with the overcast skies & ominous weather, I felt like I was in prehistoric times like portrayed on TV, with volcanoes blowing up everywhere, & dinosaurs stomping around between them under black skies.
Backpacked in from Summit Lake North campground. About 15 miles in sandals. Very slow and painful process going up to the cone from loose volcanic gravel. Nice to walk down into the cone. Great view of Lassen.