I don't have any personal experience with the IRO, so I can't comment much on the bike and loading it. IMO, doing 150 - 200 miles a day is very ambitious. Just for reference, I think that most of the folks on this forum average about 70 - 80 miles a day (with an average speed of 10 - 15 mph).
Without knowing your physical condition and experience, I can't comment on what a realistic goal for you would be, but I think it's better that you understand your limitations and set reasonable goals. I have read about a few folks on this forum who pushed themselves early in their tour and ended up burning out and aborting it.

As far as sleeping arrangements, you can try to search for "Stealth Camping" on this forum and you will get some ideas.

FWIW, I am a SLOW rider with an average speed under 15mph (all the time!)

Ravi