A big thank you to everyone for your input and suggestions! I ended up finding a used K-3 with the 18-135 lens for a reasonable price through a reputable seller. It should be here today! I can't wait to give it a try. I hope to add the Pentax smc DA 50mm f/1.8 Lens for portraits, and either the Pentax HD PENTAX-DA 55-300mm f/4.5-6.3 ED PLM WR RE Lens or Pentax HD Pentax-DA 55-300mm f/4-5.8 ED WR Lens soon. I prefer the faster and quiter auto focus of the first, but the second working with my K-r as well as my K-3 is a plus, not too mention the smaller price tag! Although Amazon says that it works with my K-r. Limited functionality? Or incorrect information? Anyone know for certain?
In the meantime, I have been shooting in RAW and playing around with post processing in DxO. I can't believe the difference it makes! It helped a lot with the noise and some with the loss of contrast and color in low light. I think the resolution limitations of my K-r are the biggest factor limiting my results. I'm excited to try the K-3 for the volleyball games tomorrow with it's DA 18-135/3.5-5.6 WR lens.
On a side note, I regret not learning how to make my old M50/2.0 lens work on my K-r sooner. I loved the results; however, having young (active) children, I definitely need an auto-focus prime for portraits. I was lucky enough to catch a honey bee in flight (and in focus) with it though.