Have you tried craigslist yet? VRBO.com is also a great option for short term vacation rentals...
I am a real estate agent for Century 21 Sunbelt Realty in the Cape. Even though it is considered our off season, there is still a market for rentals/leases. Things that may affect how long it takes to find a potential renter are the length/terms of the lease, location, size, pets/no pets, and of course price.
In addition to working with buyers and sellers, we also offer services to homeowners like yourself. If you would like additional information, please feel free to contact me anytime. Cell 239-560-9139 or firstname.lastname@example.org
Century 21 Sunbelt Realty
Jones and Co Realty