There is value to both being prepared and being spontaneous and having a fun adventure.
I would suggest checking out the target area and finding some fun, cool things to do for your player outside of baseball and the tourney. Sometimes these extra side-trips turned into the real memories. One trip, we found a water cave to swim through and we all still remember that as one of the coolest things ever.
Make sure the 5 y.o. gets plenty of attention and has plenty of entertainment. Try to arrange for him not to have to go all the time. It will make it more enjoyable for him and everyone else when he does go.
For really hot days, get a small ice chest and a couple dozen cheap white rags from dollar store. Roll them up, wet them down and throw some ice on top. Put the ice chest in the dugout and let all the players use these to put on their heads and around their necks between innings. They love it and it makes a world of difference.