Hey- I've read through some posts here re: no-sanding protocols. I have a city rental and know sanding is going to stall my process if not shut it down. I would appreciate any winning pointers I may be missing. I know:

1) The floor has to be thoroughly cleaned and dried.

Is a steamvac of any help with this?
Am I right that amonia is the best choice of cleansers?

2) Any gaps between boards and rotted out spaces around radiator can be filled in with wood putty?

3)Then just lay down the polyurethane?

Is there any kind of color/stain/finish/ treatment before the polyurethane that could improve the appearance?

Lastly, how many coats of polyurethane can I put down? I just raised a litter of puppies in my apartment and there's a good chance there will be more in the future so I am aiming for the highest durability possible!!

I really do appreciate any tips.

Thanks