For IK's I think you'd like runs that have a big channel and few rocks. I've taken folks out in IK's several times, and rocky small runs like deckers were a major pain. Experienced kayakers can thread their way thought the rocks, but IKs seem to get hung up and stuck and sometimes the rocks cause swims.
1) Pumphouse - colorado river
2) Filter plant - cache la poudre
3) Cemetary - roaring fork
4) Grizzly creek to glenwood - colorado river
5) Moab run - colorado river
If you are learning, be careful at peak flows in june, and watch out for each other. On IK trips I've taken family and friends on we have lost paddles, had some nasty swims, and some shaken IKers. Without someone who is experienced you could quickly get in a situation where you lose gear and are hiking out. Chasing and stopping boats can be difficult once someone swims. Make sure to clip all your gear into your boat so you don't lose it, and make sure you dress with warm gear in case you swim. Wetsuits and splash gear are a good thing to have even in the heat of the summer.