future planning... you need about a 5x5 room for all the major categories to fit all the junk you will need with a bit of storage and some aesthetic appeal : bedroom/comfort, kitchen (can be about 1/2 the 5x5 if you don't do many storage chests), crafting (assumes smelters and windmill and such are outside, else need even more space and height and smoke vents), even trophy display (optional, but theres a lot of them). Its possible to combine kitchen and bedroom if you really squeeze it in and loft some items on a wall.
what I have been doing is hearth over bedroom ... this nets me the comfort from below but I don't have to deal with a chimney, the top level has all the fires and an extra high roof with ventilation.
anyway, a single hearth will do a 5x cook rack, as will 2 campfires placed carefully. Its a little harder to get 3 items working together but its doable. I usually just do 2 hearths, since you still need the cooking pot... but I long sense realized there are 20+ ways to do anything in this game, all equally valid.