Is this for making fine art or happy snaps? Do you want to constantly experience the park through the lens of your camera or do you just want mementos of special times. Do you plan on prints? Bigger than 5x7? Do you realize how heavy even a small camera can get after 6 hours in the park?
OK. Small rant - Sony bugs me in general. I hate their proprietary chip tech (memory stick vs. everyone else's SD). And they are known for higher failure rates in general. Not to say your choice is a bad one though. but there are a LOT of unit like this one with a variety of features and qwuality for a widely varying price. The Sony sensors actually aren't that bad. Except for the noisy Panasonic chips, most any camera in this price range won't be bad.
You realize you will spend another $50-75 easy on extra memory and batteries? I prefer to stay with cameras that use rechargeable AA's. As always, I would recommend Canon. Equivalence here would be an
S5IS but ~$100 less. Same set of features basically except for batteries and storage. Read the review to get some ideas.
Either way, cameras in this class actually weight a lot. Have you considered a good P&S instead?