Everyone's experiences and preferences are different, so you do what seems right to you.
This is a really busy day, with a lot built in and not a lot of time to just enjoy the experience. Personally, I love letting my kid play with Bruce the Shark or in Spaceship Earth. She loves it, and that's why we're there, to let all of us have a magical experience. We took a lot of time with Agent Perry - we did 3 adventures, and that took up a big chunk of our day. Test Track was down during our FP, so we stopped and played at a playground they had set up and got a cold snack.
The only thing I had planned out was our lunch (it was the one table service meal we had for the entire trip, for our anniversary) and our FastPasses. We winged the rest, grabbing Fastpasses as we could (scored Test Track later in the day), playing Agent Perry, and just exploring and looking at the countries. We only made half of them and had a great time.