Cloths in one sidecase, sleeping bag in the other. Stick the sleep apnia machine in the topcase, and tie down your tent on the passenger seat. If you sleeping bag doesn't fit in the sidecase, stick it in the topcase, you tie it down to the pillion seat with the tent using the grabrail as your tie down points. Stick your rain gear in with the sleeping bag or sleep machine, whichever has more room.
I managed to bring things for a camping trip, an extra FJR seat, hydration mounting system (which is no where near as small as the skyway system), and some misc items on my bike before and had no problems. I did this with an aux fuel cell which takes the place of the pillion seat also.
I think a big part of it is cutting back on your cloths. If your taking more than a side cases worth of cloths, your taking way too much on a camping trip. You never did say how long your camping trip is either.