This is the thing to do when you come to Hawaii! If you are in good physical shape and hike regularly you should really really try this out.
This is a hard hike, I wont mince words here. The elevation is steep and the Guide (Our Guide was Jon) was very helpful showing the way and making sure everyone was okay. This hike was the Highlight of my trip.
We only had 6 of us total including Jon, we all were at different paces at times but no one was made to feel bad about it but again I do need to stress that this is a Hard hike. Its little less than 1000 ft elevation gain and about 2.5 miles total distance. Its hard, but sooooo worth it. The Lava Cave alone is worth it.
I wouldn't plan anything afterwards just to be safe incase you are mega tired. I also recommend bring more water than you think, we had our 32 oz Hydro flasks and ran out just a bit before the end of the hike, it was all good as there was refills at the van when we wrapped up.
Again the best part of my whole trip, I will come back and take this tour again it was so good. Thank you Jon for your guidance and the great hike!