OK, I have been on the phone with Civil Defense, the contractors who operate the County viewing area, and Kalapana Lava Tours, and this is what I have learned.
Kalapana Lava Tours, which runs about five tours a day from Uncle Roberts (next to the Kalapana Cafe), is fully licensed and insured, per the viewing area operators.
They are able to run this tour, which is over private property, because their ohana (family) owns all that land. All the other tours are trespassing, and they are gradually being shut down.
Arnott's was coming out there, and that MIGHT be the Hilo guide mentioned in the closed topic, but they have been informed that they don't have permission, and did not come last night.
One or two other illegal tours have been shut down, and one or two are still operating.
Further, there are all sorts of tourists coming and heading out to the ocean entry, trespassing, no guides, behaving very STUPIDLY.
The current hike is about 3 1/2 hours. It is fairly rugged. They do go right up to the lava if it is safe. These local guides are from the area and I'm sure they know the terrain as well as anyone. I cannot say whether their judgment is as good as a park ranger's; you do take your chances.
The phone number for this tour, the ONLY legal tour, is 808-936-0456. Please do not go wandering the lava fields on your own. Aside from the danger, it's highly disrespectful. This land belongs to Native Hawaiian families and it is not a park.
I will cross post this on the Lava Viewing topic.