Martin House is within walking distance of the ferry landing in Nantucket town (though we were glad we had our bikes with us to balance our bags on as we walked there). It's a large clapboard house with a comfortable porch off the side.
You can get rooms with or without private bath here--my parents were the ones who got the room with the private bath (and a lovely canopy bed and fireplace) on the first floor. My sisters and I shared a large room under the eves on the third floor, with the bathroom (shared with one other room) next door.
The rooms were comfortable and cozy, decorated with old-fashioned prints. Our room had two queen beds, a wicker night table complete with fresh flowers and glossy travel magazines to read, and a rocking chair nestled in a dormer. It was like visiting your grandma's house, if your grandma happens to have a large, rambling, quaint, flowery house on Nantucket.
There is a large continental breakfast each morning, which includes juice, coffee and tea, really good homemade granola, fruit, and homemade baked goods. Grab your food from the sideboard in the dining room and head out onto the porch to eat if the weather's fine.