We probably did it over the space of 5 days. The only time the stairs were really un-useable was when I painted the treads. I did ours first thing in the morning, right after the kids went to school. In about 6 hours it could be walked on with socks. The primer dries super fast, so you wouldn't have to worry about that. Also, some people do every other step on different days so they can continue to use the stairs all day.

Good question and you seem to be taking a nice, thorough approach. I think the most important question is whether the current layout works well. Does it meet your needs well? Where would the additional 6 linear feet of cabinets go, and what unmet need will they fulfill? You could post a "help for layout" thread and see if we can come up with a better layout than your current one. If so, you may be more inclined to replace everything and move the layout around. If not, it may tip you the other way.

Let's compare to cost of reSURFACING the treads = $200 stair/riser combination. Hmmmm. The $40/tread looks pretty good. If you have 10 treads = $400. If you have 20 treads = $800. Hmmmmm...I'm not seeing an issue. The 'average' tread count (just off the top of my head) is around 13. That means $520 for the trread/risers to be refinished. That's one HECK of a deal! Let's look at the cost of a PROPERLY installed (to code) railing. If you have 10ft the cost of the railing $80/lf = $800. If you have 20ft then it costs $1600. Shall we assume the railing INCLUDES the spindles, newel posts, AND matching the stain of the treads??? If it does, you are in a SWEET spot! To save more money, you would have to break code laws and have a dangerous railing...and that costs way more in the end...than if you just do it properly the first time (home owner's insurance does NOT cover damage/injuries with non-code meeting items...like railings and stairs). Remember: Stairs require knowledge of AND COMPLIANCE WITH 15+ different code requirements. The $80/linear foot = paying for a company to KNOW what those are...AND to do it properly. The materials are relatively easy...it's the KNOWLEDGE that is so expensive.

The last time I had a pair of Louis xiv chairs restored I paid in the neighborhood of $4k each but it increased the appraised value quite a bit more than that. I can't help you with any place near Cleveland,I wound up sending mine to France.