What about vinyl plank flooring? Comes in a range of colours and can be put on stairs too. Because it's planks, you could do part of an area at a time and just move part of the furniture at a time too. Also cheaper than hardwood and very durable. You could either stain the existing wood floors in another colour and choose the vinyl to match, or I suppose you could put vinyl over the hardwood if you want. (I've had hardwood, and actually prefer carpet to that, as dogs do scratch up the finish significantly. Also, no shrinking and creaking over time.)