Ive been experimenting with some IK as well and have gotten a pretty decent and efficient system working. Basically I am using the IK bones in the rig, a LegIK node (so the legs follow the IK bones which has animation baked into them) and then using traces to get an offset value, and then using that to transform the IK bones up or down (I also offset the hips). This way I can have IK that works during the locomotion cycles instead of just standing still. It still needs some work but its pretty good for starting out.