Mary's townhouse is in a great location for exploring Seattle. Fremont is a short walk and there you can find local shopping, restaurants and a grocery store. There is also a park just down the street from the house where kids can play. My kids loved it. Wallingford is also within walking distance, although it's a bit farther.
The house itself has everything you'll need for a very comfortable stay. The beds have several different types of pillows for different sleepers, the bathrooms are stocked with towels and toiletries and there are fans and extra blankets if needed. The kitchen has anything you'd want, including spices and basic staples. There are items for making cocktails and plenty of cookware.
While there is sleeping for up to 10 people, it would be most appropriate for 5-7 adults.