So, my son went to moloka'i with school last month and it's absolutely been the highlight of his time living in hawaii. He actually stayed in Kalaupapa for the weekend and his group id volunteer work with the NPS, but also got the full tour of all the important sites. He's talked so much that my husband and I want to do one of the tours. So I would say totally do it.
Uber would be pretty expensive, but if that's your only option, then that's what you'd have to do. I believe the tours use Makani kai air which isn't located directly on the main airport terminal. it's located down lagoon ave, not that that matters much. . If you're using a different carrier, then disregard.