There is lots of places... I have no clue as to your fitness, but there is a ride at 75th Street brewery right there off of Wornall on tuesdays at 6:30, the Jerrys Bait Shack at about 95th and Quivera ride on Monday at 6:30. On thursday, at 71st and Mission there is another Prarie Village Yaght club at 6:30. Johnson County Bicycle Club....
http://www.jcbikeclub.org will have all the local stuff, I think this to be more moderate stuff.
If you are looking to really mash and have the legs to do it, then there are some stupid fast rides a little east of you on Tues, Wed, Thurs and Saturday.
Tuesday starts in downtown Lees Summit, Wednsday starts at the Bike Shack in Grandview, Thursday starts at Summit Bikes in Lees Summit, and Saturday there is the Big Dog ride at Einstein Bagels in Blue Springs.
Kansas likely has some stuff, like I think they are starting their tuesday night crits soon, and there might be others here and there.
There are lots of good shops, Trek store is ok, there is one on State Line I think, there is Bike Shack, Summit Bikes, Bike Source, Bike Stop... all within a 20 mile radius give or take... pm me if you have any other specific questions, Id be glad to help... welcome to the KC area.