Shoot, I guess it's long past your anniversary...hope you had a great time. Since I have this ready to go I'll post anyway as someone else looking for info on Door Co. might find it useful.
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Another vote for Al Johnson's, but make a reservation if you can because it will be busy.

Frankly, I'd check out White Gull Inn for the fish boil but only stay for the cooking part, which is kind of a show. The fish isn't all that good and it's so full of tiny bones that you spend half your meal picking them out and trying not to choke on them. I didn't think the rest of the food was that great either. I'm normally a fish fan, but won't do a fish boil ever again.

Penn. State Park is great. You can hike, rent boats, etc. There is a nice little restaurant across the street from the park entrance with great wood-fired pizza.

On the way up, stop at the Shipwrecked Brewery in Egg Harbor.

There is another WI state park called Rock Island SP that you can only reach by taking another ferry (passenger only, no cars) from the bay located on the NE corner of Washington Island. The island was once privately owned and the guy built a huge Viking style boat house and a couple other buildings. The island also has WI's oldest lighthouse. There is an enjoyable hiking trail to the lighthouse and around the island.