I would get a lot of advice first.
only if you have help And a good breather don't trust a paper mask,,, cough, im juSayin
that's a big job....what are you saving cash wise doing it yourself? if it's worth it, do it yourself, I am sure you can handle it and it will turn out nice.
no. dont do it
What are your skills? <Many with basic carpentry experience can get an OkK (nor really professional looking) result. Watch that drum sander, you do serious and expensive damage in a few seconds if you don't keep moving. Lose control of it and you will have a eal mess in a hurry. Don't let that scare you off, it can be done if you have some woodworking / home repair skill. It just may wind up looking like a homeowner did it, not a pro. But I have seen some pretty rough work in rentals...
How bad is the floor? Just needs a light refinish, or is it discolored/stained and deeply scratched? How much time do you have? What are your skills? Done anything like this at all?
I looked into that when I moved into here, 5 years ago. Too much work and expense, and then your landlord raises your rent. And varnishing it, or sealing it, is not an easy process. It can end up looking very bad!