I took my wife to Cumberland for her birthday. I had been to the island but not the Greyfield. Yes, it is expensive. However, yes, it is more than worth it. Middy and Mary Jo who run the Inn are absolutely wonderful and have a staff that makes you feel at home, just like you are visiting family. Staying at the Inn makes you feel like the Carnegies must have felt.
I encourage you to stay in the Inn and not the cottages - - gives you more of the feel and experience. Getting to know the others is half the fun! Don't worry about shared bathrooms. Yes, I was worried. But it actually was fine. Everyone was courteous and thoughtful. Just plan a little so you don't take too long. We actually used the bath house behind the house, putting on our robes and crossing the driveway in 34 degree weather, and it was absolutely wonderful.
I recommend the Master Bedroom though we never used the separate sitting room. If we wanted to sit and read, we went downstairs by the fire so we could meet others.
We ended up staying another night because it was such a special place and had to switch to the North Marsh Room. Though no where near as large as the master, it was perfect as well with tons of windows and light. I actually enjoyed waking up to taps being played at the St. Mary's Naval Base. It is amazing how well sound carries across the water.
Four hints. Stay for a Saturday during oyster season so you can enjoy and oyster roast but wait to get dressed for dinner until after the oysters. Second, take the tour of the north island and make sure you plan it on a morning when Plum Orchard is open so you can tour the house.
Three, save up a little more and walk over to Gogo Ferguson's studio for a special piece of jewelry for your wife. It is a reminder that she will never take off and so perfect to remember the island. Four, use the bikes. Go to Dungeness, ride on the beach and explore the lower island. The bikes make it so easy and fun.
Enjoy!

You'll arrive by boat embarking from Fernandina Beach, Fla., and will start to get the flavor of the place even before you reach The Greyfield, as the island slides by on your right, with only an occasional house or dock. It's a mystery landscape of live oaks, palmettos and Spanish moss, occasionally divulging its secrets in the form of an armadillo or fawn. A bright young staff member will give you an orientation, including a brief history of the island which is now mostly national park, then you'll settle into your beautifully furnished room or cottage. There is much to explore -- be sure to see the ruins of the old Carnegie mansion, and historic Stafford which has been kept up at great expense by its owners. (Greyfield provides bikes for its guests, and a beautiful beach -- complete with wild horses -- is only a short distance away.) This is a family-run inn with a distinctly non-corporate feel; bring the kids, or enjoy a romantic escape, it's perfect for both.

We came with a friend who had many childhood memories of the island; after just a few hours at the Greyfield Inn and a walk to the beach, we understood why she thought this place so very special. It simply is.

The deep history is fascinating, the roads and trails and wetlands and wild animals are an outdoors person's delight.

The Inn itself is magnificent and the food quite good, though not pretentious and they were very accommodating of a pair of non-meat-eaters.

Even if it was not this good I would come again and gladly pay the freight for a chance to spend another day with Barbara touring the island.

We were there for three days over New Years and the company we met at evening cocktails was as interesting and excellent as everything else.

the Greyfield Inn is good enough inn to attract a following even if it were not the only hotel on a 15 mile long piece of undeveloped beach. I cannot think of a comparable piece of real estate anywhere. Go there, bike on the beach, enjoy great food in a totally relaxing environment.