There are some hotel options on the island. Check out some Airbnb's in the area if you prefer to go this route. There is also the option to stay in Seattle and ferry over.
Travel Note
Ferry Information
There are two ferry options;
Mukilteo to Clinton (closest to the venue)
Port Townsend to Coupeville
House Or Rental
Airbnb
If you are interested in doing an Airbnb instead of a hotel check out this link and look at some options in the area