These places can be helpful if you want to take a tour with that operator, but don't expect them to give unbiased info about other options. Check around before making your choices. Somehow, I have difficulty believing that could be possible. For real information, contact each state for tourist information. They'll send you magazines and brochures to keep you occupied for weeks ahead of time.
Guidebooks are great for suggesting scenic routes and contact information for tourist attractions.
Photocopy the pages that are applicable and take them along with you. When you arrive, check out local entertainment newspapers, review the local daily, look at posters, or just ask around. We got up early to join the group and discovered that the little park had small boats that we could borrow to paddle around the cypress knees in search of alligators. We not only found alligators, but we had a great time exploring a bit of swamp. Ask friends for tips or contacts.