I just bought a severely distressed rental duplex. It has hardwood flooring throughout. Floors have been neglected--worn, stained, buckled, etc. My idea is to thoroughly clean, then apply a darker color stain, then apply a couple of coats of poloyurathane. Is this too easy? I'm not in any position to do a "knockout" type of job but figured this would look better than it looks now. I guess I'm just trying to avoid sanding. Thanks for any and all suggestions!

Do it..
what the heck. You can always sand and re-coat if it does not work out too well.

I would fix the buckled areas, and then sand, stain and finish.

Don't think about trying to stain or finish, without sanding.