First, you need to confirm that your floor is solid wood and not just a thin top laminate. If your floor IS solid maple all the way through, or at least the top third, then you should be able to sand it down, assuming that it hasn't been done too many times in the past, since once you sand off so much the tounge/groove is exposed. I have never personally done a maple floor but I have worked with maple for casework and built-ins, etc. What I remember most is how increadibly hard this wood is. This would lead me to believe that you might not need to start off with the most coarse, very agressive grit on the floor sander. Very hard woods seem to respond very well to medium or medium coarse grits. Also, the old stain/finish has probably not soaked in very far - because the wood is so hard - so you probably don't have to take off a ton of material. When it comes time to stain and try to get it dark, you might have some difficulty because the wood is so hard that it doesn't absorb very much stain and pigment. I would experiment on a piece in a closet, or a scrap you have or buy. I would definitely try samples of the darkest varieties, leave it on for a while, maybe 10 - 15 minutes before wiping excess. You should be able to approximate a similar color to the oak. Stained maple tends toward the light brown/honey brown. Your dining room might also look great (with or without the finishing) with an area rug - like an oriental - that fits in the area taken up by the table and chairs. I like this look and you don't get all that noisy chair noise or any wear to your floor from table and chairs moving around. good luck!