I have a few suggestions since I am going through the same thing you are! Both my kids were born in the winter and fall so it's hard to have parties outdoors.
1. Prueter's Sports Tae Kwon Do- they have a location in both Blue Springs and Lees Summit. My kids are taking classes from them and they love it. The Prueters are great people and from what I heard they do have good parties. I've never had their birthdays there since it wouldnt really be a treat for them since they do that every week! But their package is $225 for up to 25 kids. Includes pizza, drinks, cake and the birthday child gets to break a board. All this for 1 1/2 hours. Heres their website- http://pruterstkd.us/
2. Landmark 2 skate- For a private party for up to 50 guests for 1 1/2 hours its $180. You provide cake, drinks and paperware. Kids and adults have a great time.
3. Chuck E. Cheese- We just had our daughters party there. I spent about $180 for 11 of us. I didnt reserve anything. I used coupons I got online by joining CEC. We had 4 large pizzas, 3 all you can eat salad bar and I bought 100 tokens. But with the coupons we ended up with 300 tokens. I could have only bought 3 pizzas and that would have been fine. And my husband and his friends used a lot of the tokens themselves! We brought our own cake.
4. You can try to call Legacy park also and see what they have to offer. I know they have a lot of kids things and maybe you can have a pool party?
Hope everything works out, I have to plan another party for my son this month!