Sanding methods for uneven hardwood floors

Hi all,

Just bought a "new" home that contains original oak hardwood floors, circa 1962. Apparently due to the floor's age and seasonal humidity changes in the area (Connecticut), there is some inconsistency to the level of the floor from board to board and even across the lengths of single boards. It's not so apparent that you would notice unless you were really trying to look for it.

Most of the floor has been covered by carpet for some time, and about 1000 sq ft needs to be refinished as it has completely dulled out and has some noticeable minor scratches. Knowing this, I did a bit of research and figured that a drum sander would probably be the ideal way to go, but did come across the ezV Varathane floor sander (3 disc random orbit floor sander) available for rent, and decided to give it a shot due to its apparent ease of use. I hoped that it might be aggressive enough to get through the finish consistently.

Well, after spending about 7 hours with it (and finishing maybe 300 sq ft with just the first pass of 36grit), I realize that while it does an admirable job with the majority of the floor, there are many low spots across the floor which it just can't touch, leaving me with what are essentially patches of old floor not taken off. Some of these "patches" are the ends of a particular board that has settled, while many others are long narrow strips of finish at the seams of 2 boards meeting up where the edges dip down slightly. Now, what I've done so far is use my random orbital palm sander to sand down these little patches to the wood like the rest of the floor, but considering the great number of these trouble spots, this takes WAY TOO LONG!

Given that I have to move into the house next weekend and I want the floors to be set by then, I have to make a quick decision and hurry it up! Which brings me to the following questions:

1. Is it crazy for me to even consider trying to finish the floor with the current method - ezV Varathane and then touching up w/ the palm sander? (Crazy, yes?)

2. What are the implications of me just "being lazy" and leaving some of those old finish patches on the low spots of the floor and applying new finish over that? Would it lead to massive color differences or incompatible mixing of old and new finish?

3. Should I just stop being crazy (see no. 1) and rent a drum sander? Would the drum sander dig deep enough (I would think so)?

4. For the small section of the floor that I've sanded perfectly so far, do I need to run the drum sander again over that?

5. If the rest of the floor is "half-sanded", with old finish patches distributed throughout as explained above, by using a drum sander can I get away with using a finer grit to start instead of the typical coarser grit if I hadn't done some of that sanding already?

6. Lastly, I do have a question regarding an area of the hardwood floor that is in a separate room and actually looks decent already, as the previous owners had used and maintained that area of the floor without carpet over it like the rest. After removing the carpet on the rest of the floor, this currently finished area is basically a continuation of the same wood floor from a hallway that does need refinishing. Can I leave this room alone and hope to match and blend the hallway's new floor finish into it? Or should I just refinish this room the same way as all the others so that it blends into the rest, regardless of the fact that it looks okay by itself now?

I hope you got through all of this with your eyes still open. Ia know I barely did.. Seriously, though, any help is very much appreciated!

Thanks... -Lukas