Let me preface this by giving you a little bit of caution; hiking Kalapana can be very dangerous if you don't follow the rules and use a little common sense. So here is my check list of supplies and caution:
*Wear good shoes, the lava is sharp, it's slippery and it's full of holes, crevices and loose rocks
*Bring more water than you think you'll need., I bring at least 3-4 bottles for the 3 mile hike and leave a few more in the car.
*Take a Flashlight ...and bring a backup. The ideal lighting for photography is just before sunset, so if you stay for that, you're going to be walking out in the dark. Grab a few LED headlamps from Walmart, they work great and only cost $13 dollars.
*Carry a GPS. The landscape is black and there are no streetlights or beacons* to aim for, you can be hiking right next to the road and not see it.
*Watch the Wind. As you get close to the lava, you will notice sulfur dioxide coming out of the ground and at the ocean entries, YOU DO NOT WANT TO BREATH THIS, it's poison and it can kill you.