There's plenty of list of "What to pack" for your hospital bag but I honestly think each hospital, specially here on Whidbey Island needs a bit of tweak and peek. I would say the best resource would be the hospital themselves, but if you have time to tour the facilities before your birth day, that would be super awesome since you can adjust your bag depending on what you see is fit.
Let's take for example one of the hospitals here on the island provides towels, but they may be a little bit on the smaller size, you may want to bring your own towel then. Or pillows, I think that's the big thing for me, I don't like fluffy pillows, the flatter the better! When Charlie was born, I brought my own pillows and Ben got to used the pillows they gave me at the hospital. I see the opposite with my clients though, a lot prefers the fluffy pillows and the dads get the flatter pillow. These may seem to be tiny inconvenience but trust me, sometimes its the little things!
Hope my list helps! Just follow this link.