Greek Island Hopping Advice Sought

Hi
I intend to spend two weeks hopping some of the greek islands but am a
bit unsure whether to just buy a flight and throw all caution to the
wind. I do have a very good book on the subject but am tempted to seek
an organised hopping package, although more expensive peace of mind
comes at a price it seems! Does anyone have any experience island
hopping who would care to advice me either way? Is it as simple to do
off your own back as the books suggest to find accomodation in peak
season?
thanks
Meg