Just one thing you need to realize. Yes, you can hunt the island without a boat or dog but, if you hear people talking about high water, take that as a warning. Even when it is not high enough to require a boat, it may be high enough you'll need a dog or alternate type of retrieval. There are also some units with deep mud that you can sink pretty bad in. I know of at least one hunter that was rescued by a helicopter and his waders were left on the bottom when they pulled him out.
Generally, the ODFW staff will tell you if you need a dog for a particular spot. On the westside, I've seen them deny a hunter a spot because they had no dog in higher than normal water.
Save a Salmonid, shoot a sawbill