I have been looking at Key West too, however they have a mandated mask order in effect even if you are walking outside by yourself and on the beach, this is only in the city limits of Key West and as of now August 30th, 2020. If this doesn't bother you I can recommend a place called the Curry House Bed and Breakfast, very nice and great home cooked breakfast (although) that might be on hold as well I have noticed a lot of hotels that say breakfast included are not actually included because of Covid 19, nice quiet residential area with all the nice homes to walk around and look at and it is easy to walk to center of Key west and even closer to the marina with boats and shops, bars restaurants. We have opted to go to Islamorada as we do not want to wear a mask while walking around outdoors by ourselves. Anywhere else in the Keys seems you only have to wear a mask into establishments and in restaurants and bars only walking to and from your table/bar, otherwise masks are ok off your choice.

https://www.google.com/maps/place/Curry+House+by+Vacasa/@24.5583797,-81.7990919,17z/data=!4m11!1m2!2m1!1shotels!3m7!1s0x0:0xe5e204b24ed6cb84!5m2!4m1!1i2!8m2!3d24.5582359!4d-81.798979