Hello, OP! I went years ago, mostly to chill on the beach but I went on two excursions.
1. The Tall Ship - a beautiful trip around parts of the island. At the end, they serve golf ball sized, homemade chilled coconut balls that were one of the best treats I've ever had.
2. The Volcano Tour - I can't remember how we got there but I think we were driven to thee top of the mountian in jeeps or a bus. We stood just beyond the smoking crevices where the heat and smell of sulfur was almost over-whelming. It was very "touristy" with trinkets for sale, etc. and the most interesting part were the goats that have evolved in a way that they thrive in that acrid, smoldering environment - they stand on the blackened Earth, breathing in the heat and fumes without any problem while you're praying for your next fresh breath of air! **If you or your children have any breathing or heat-related illnesses, please think twice about this. I almost passed-out and I had no such issues at the time.
All in all, it was a nice trip but again, it is very hot this time of year, even on the beach - far hotter than St. Johns, where I vacationed during the same months another year.
Bon Voyage!