I rode all over the west last year on a Suzuki cruiser and camped for 17 nights, and in addition to the bare-bones list you made (but without the C-PAP) I also had a backpacking stove, mess kit, coffee makings (cone, filters, etc.), Thermarest ground pad, hatchet, flashlight, tools, some reading, a first aid kit, extra shoes or sandals (unless your riding boots are damned comfy), and plenty more. I had some things in a small duffel, like the sleeping bag and other small light things, and others were just bungee'd down, but there wasn't much I had I didn't need. (F'ing Junior is right about non-cotton t's and underwear, btw. And don't forget if you're going to places like Yellowstone or the Grand Canyon, like I did, you'll be buying more t-shirts there.)
I liked the loops of parachute cord idea for bungees, too. Why pay Aerostitch ten bucks for a purpose-made strap that does the same thing? I'm camping next weekend--that Morro Bay trip--and just sized my essential things on the FJR and have been wondering about your exact question. Noplace for tiedowns. I'll be making some 'chute cord loops pretty soon. A tank bag and my Yama top box and I'll have room for everything but a hitchhiker.
