The trips where we planned and researched everything were a mixed bag - amazing for the people who were just along for the ride, ridiculously stressful for the ones in charge of planning. I'm still burned out from planning a trip we took two years ago. It was a nice trip, but I was worried sick the entire time that this or that wouldn't work out, or that people wouldn't like it.
We took a trip to NYC about 5 or 6 years ago where we literally showed up with no agenda at all. Neither of us had researched anything, we just went for things we had heard of or discovered along the way. I kind of liked that trip because it just felt so free. We probably could have packed in more, but I just keep telling myself that now we have a reason to go back.