We're now in Thailand and looking for a trek into the mountains near either Chiang Mai or Chiang Rai. There are companies that advertise however they all come with either elephant riding or visiting a local village. We really don't want to ride elephants and we hate the idea of visiting a 'human zoo'.
Yes most of the tour companies that advertise in hotels and hostels run the tours that will take you one of those camps where the elephants are treated horrifically. There are some decent places though if you do research.
We did hours and hours, and decided on doing a half day with a hill tribe and their stunning elephants with Chiangmai Elephant Land. They offer a full day where you can trek as well. Extremely well run and excellent care for the elephants who are all rescue. No riding either.
I'm glad that you are taking the time to research and not just blindly going into it like so many other tourists that end up supporting the awful treatment of elephants!