M.W.
My son has a July birthday and since he was 3 we have had birthday parties with friends. I generally have them earlier in the morning since it is usually so hot and most kids are up early anyway. The first year we did slip n slides, pools and sprinklers. The second year we went to Chuck E Cheese, then the next pump it up~Granted it cost more, but they were in charge and I LOVED it!! Last year one of my sons presents was those big water slides so we did that along with a campout. This year I wanted it more low-key and didn't want a millon kids at our house with all the rain we've been getting, so we are just going to the pool on a Sunday afternoon. Most of the kids invited have passes and we figured we'd do pizza and cake there and the kids would all have fun.
It seems like with any of my kids' parties all they really want to do is play and have fun with their friends so no matter what you do they will have fun. There are some gymnastics places in Overland Park that are really reasonable too. I think Elite is only $110 for 10 kids to play for an hour. You can add time to it and kids if you like and it is still cheaper than most of the others we looked into. www.elitegymaq.com I would just go with something your daughter is into and center the party around that. We had a real princess (Ariel) come to our house for my daughter's fourth birthday this year. It was less than $200 and she had the kids completely entertained for 1.5 hours. That price included our invites, party favors and craft for the kids, plus my daughter got some special presents from Ariel. I think it was called princessatmyparty.
I hope that helps you a little. I am the same as you when it comes to planning (or at least used to be) I wanted it all to be perfect from beginning to end, and then I realized that it is perfect if the birthday child has fun and her guests leave smiling!!
Good Luck!
Oh, I also wanted to say that when we do have more expensive parties, we don't usually buy our children big gifts. They get so many things from family and friends anyway and the party is their gift~my kids have never asked either, so hopefully we can continue this.