Book your flight early with Easyjet to Athens, travel internally and pick up accommodation there !
Last year, early October, the likes of Kos, Kalymnos and similar places were completely dead - good for Gail and I but not for the tourist industry ! If the prices are that high, ignore them. If the quietness of last year is repeated and they are contracted for the accommodation, then deals will abound. - prices will plummet. (If they don't then cash flow and ccontants will tell them to sharpen their pencils !). Bite the bullet and wait a tadge as, using Easyjet and (interenally) Aegean Air, you'll walk those prices anyway !
It'snot like it's luxury accommodation - don't get me wrong, it's exactly what Gail and I want to escape the madding crowd - but there's only so much cost that that level will stand. Make 'em have it.