Do you have any vent opening in your floor?

Or can you see any nails heads or anything shiney between boards?

If you cant see any theres a good chance you still have enough meat on the floor to do a sand.

The biggest concern is running a drum sander. Without proper handling and experience it literally can take a split second to ruin the floor.

If you plan on renting one i suggest to see if you can practice or get some one on one training before hand.

Biggest tip i can give you is whenever the sand paper is within contact of wood. Always keep it moving. Never let it just sit.

Good call on the floor vent!

After looking a little closer at my floors, I've come to realize there may be more meat left than I initially thought. I'm going to bring a pro in to give me an estimate before I do anything.

Good idea to bring in a professional to give an estimate. But if your only intention for doing so is to get guidance from the professional for a DIY refinish, then be upfront about it and pay for the consultation.