The most difficult part of the process was that the carpet on the stairs had some type of clay based padding which apparently was used a lot in the 70's.... over time with the foot traffic on the steps it caused it to break down and was stuck to the floors. We (and by we I mean Glenn) had to carefully scrape it off. He had to wet it down to try to soften it.. there wasn't anything we could find that would help other than water.. But he eventually got it all off :) They came out great!
We decided to go with a dark walnut stain on the first floor and kept the natural color on the second floor.
Second floor bedroom sanded and with one coat of poly.