Moderate to difficult. It can be done from either way, but west to east, using two cars, is suggested by experienced hikers of the trail. Bring plenty of extra water, and never leave the trail posts or cairn until you have sighted the next. It is very easy to get lost.
Good boots go without saying, but gloves are a help.
One eye off the trail, and you're tripping. Jagged chunks of unstable lava of every size create the landscape. The newer part contains a limestone island, a bit of a respite, but soon hikers enter lava tubes of the Bandera Flow. The vegetation is sparse, the landscape stark black, with ropes, and odd sculptures flowed a thousand years ago. One can only imagine the smoke and fire that filled it once long ago.