OP, you said "I think much of my anxiety is from the fact that I have never been there before, so maybe I will calm down once I arrive." I'd like to recommend that you take a deep breath and relax. It is really easy to over plan and that can make for some added stress on the planner if the parks are more crowded than expected, weather doesn't cooperate or rides break down. With a large group, I would advise planning to meet for some meals and some rides, but it might be easier to have some separation as well. This is especially true if some groups are early morning people while others are not, or if some want a midday break while others want to be in the parks from open to close. You'll find out early in your trip what works for your group so don't be afraid to make changes on the fly or to let the other families modify their own plans. With a month long trip, you really will be able to see everything you want. Have a great trip!