3 YR Birthday Party questions at the park

angiemom2be

My DD's 3 year old birthday party is in 1 week at a Park with a rented pavilion. For the first time, I have invited daycare school friends and dance class friends this year and as I am fairly new to throwing kid parities for classmates etc, some things have come up that I am not sure how to handle with the schedule/party.

My initial plan was as everyone was arriving, we would have a t ball set and have the kids take turns batting and getting the ball until everyone gets there. Then when I think everyone has arrived, we would eat party food, do birthday cake, and then open presents. And after all of this, we will go to the playground area and play. Right now, there will be about 11 children including my daughter and about 24 or so adults.

First question is what is your opinion on this schedule?
Should the order of things be eat party foods, cake, presents, play?
Should we open gifts there at the park? Or whisk these away to be opened at home? 

My only other experience of a kids party of a school mate was at a gymnastics place, where they whisked away the presents to the car, the kids played, then they served cake and drinks to the kids, parents got no cake and only a drink if you went to their cooler and helped yourself.

I want to be a good hostess and make sure everyone has a nice time, especially and most importantly my DD.

I know there are so many ways people do things now days but don't know what is best for this many people in this situation.
What are your thoughts?