My husband and I are in our 40's. We are planning on going to go to Door County for the first time. We would like some recommendations for activities, places to stay and restaurants. We would like to stay at a place that caters mainly to adults. We don't want to hear a lot of kids and we would like to relax.

White Gull Inn in Fish Creek - wonderful place to stay and has a wonderful restaurant to match. Stayed there many times...

What part of DC are interested in? We stay at Pheasant Park http://www.pheasantparkresort.com/
in Sister Bay. Sister Bay Bowl has great fish and prime rib, on Friday they have a special. Husby's and Northern Grill are both good.

We aren't sure which area we would like to stay in.

See a performance at Peninsula Players...great theatre on a summer eve from one of America's oldest theatre companies.

I took my east coast hsb (I'm a former native) to Door County last summer (I had not been back for many, many years) and we had a really wonderful time. We stayed at the Blacksmith Inn which is on the lake side, much less developed. Very small, right on the water, very quiet. One building is historic, the other newly built but furnished in shaker/country style. If you're so inclined they have kayaks. Also bottomless bowl of buttered popcorn at night, dvd collection, homemade cookies -- I cannot recommend them enough.
We did the fish boil at the White Gull Inn one night -- the bay side is much more developed and much busier -- I think you have to do one of these and theirs is the oldest. It was a shock to see so many people after being on the lake side !
One day we drove up to take the ferry to Washington Island where we had lunch at the Washington Hotel and culinary school -- really a treat.
Of course you have to see the goats on the sod roof at Al Johnson's Swedish restaurant -- good lingonberrys too and wonderful selection of Dale sweaters across the street.
We also enjoyed a visit to Linden's Gallery in Sister Bay -- the Lindens have travelled all over SE Asia and China and have an incredible collection of Asian art you would never expect to find in such a remote place.
My husband had to admit Wisconsin was not so bad, after all

Do you like to bike? This is one of our favorite activities in Door County. We drive from Minneapolis, so we always take our bikes with us. there are plenty of quiet back roads. If you like to hike, the state and county parks are also good for that. I am not a shopper, but many people spend a lot of time and money in Door County just shopping.

There are some very good galleries and some truly schlocky galleries if that sort of thing interests you at all. Edgewood Gallery is also one of my favorites to visit. There are a couple wineries you can stop in at if that is your thing.

We always get places with kitchens so we don't have to go out to eat for every meal, so i can't help you a lot with restaurant recommendations because I can't remember the names of the few we always visit.

The time of year you will be visiting Door County really affects the kind of visit you will be having. Peak times are end of June to end of August. And, it can be absolutely crazy then.

I was just about to suggest the White Gull Inn in Fish Creek but I see it is already mentioned. It is really quaint and romantic, not too many families either because it is on the upscale side.

DH and I did a petal boat ride on Kangaroo Lake. That was fun.

Re: places for adults to stay in Door County.
The Egg Harbor Lodge (Egg Harbor) is adults only and has spectacular sunset views over Green Bay. You can walk to most restaurants from there. In Ephraim, there is a great B&B type place a block from the beach called" Lodgings at Pioneer Lane". Check out their websites and you'll see what I mean.
eggharborlodge.com
lodgingsatpioneerlane.com
good luck!