See
The Rimon is a lovely clean place. But I dont know who gives the Kosher certification. Shuls are a 20 minute walk and on a rainy day it can be difficult.
The Ron hotel is also nice and has Glatt kosher food
The newer part of the Tel Aviv Hotel is clean and might have Sabbath food in the winter.
The Merkas is clean and should have kosher food
Ascent is a Hammish very clean and affordable hostel with family rooms without food.
There is a take out food place called Mendies which I am told has good food. Also the is a lovely Sabbath small family restaurant called the Eshell which I highy recommmend for its good food and ambiance, right in the center of the religious area.
Warning Safed is a lovely city except when it is raining. Check the weather at:
Click Safed and the 3 day forcast