rapids without a easy trail: roaring 20s, lava, horne,
rapids you may not be able to stop a raft in time to hike up: all of them
IE you can shoot for the plan of switching raft rower and kayaker, but don't be too upset if you row the oarrig and miss the eddy at bottom to hike up. Personally, I am from the SE and ended up enjoying the big rapids more rowing the oarrig or a small paddle raft we brought then in my kayak. Mainly, because I didn't like being pushed around in the kayak and every flip was washing machine super cycle...not to mention the annoying eddies at the bottom. The whole drinking all day in the oarrig was pretty sweet as well.
Regardless of what you do, it's all good.