The bay side can have a LOT of ferocious mosquitoes if the breeze is light or non-blowing. Also, getting reservations in the SP can be hard so start early. Also watch out for the ponies. THey're fun to watch but are totally habituated to people. I've seen them steal $30 worth of picnic food from a bag in the front seat of a car (doors closed windows open) in about 10 seconds while the driver was selecting the key for his camper. THe ponies don't chase easily and they bite and kick.
The park is a great place to go and should not be missed.