I'm way over thinking this but I'm in a newborn fog and decision making isn't my strong suit!

My daughter is turning 3 in October and she loves birthdays so I definitely want to do something for her with a few friends but I have zero desire to host at our house.

I can rent a room at the local park (weather is too iffy for outside unfortunately) but then what do I do to entertain a bunch of 3 year olds other than serve food? I could host it at the gymnastics place but we've already been to a bunch of parties there already. I could also host it at a place that does Lego/building parties, my daughter loves it there and would do great with it but I'm not sure all of the other kids would enjoy it and it's pricey for them to not really get into it. Any brilliant ideas for me? I was thinking about a Goldilocks or Fairy Tale theme but I'm open to ideas!