E.B.
If you have a mixed age group or willing adults, try field day games. You can find tons of ideas online, but we use The Three legged race, Gunny sack race, Wheel barrel race, any kind of relay race, Water ballon toss, Egg and spoon race, Stick horse race or make an obstacle course. Get some ribbons, a bag of candy, or fruit snacks or some dollar store trinkets as prizes and skip the goodie bags.
We have also had everyone bring a bag of water balloons or a squirt gun and had a major water fight. Remind everyone to bring towels and dry clothes.
If you know the location pretty well make a scavenger hunt with simple clues for the kids to follow. We have given small trinkets at each clue location or just have a big prize (like the cake) at the end.
I usually make a fun shaped cake for my kids too, but last year I made a simple cake and bought a little Cinderella toy set to put on it. Since she was turning two, she really liked having the toy to play with afterward and it we just added it into the presen budget.