Upgrade light fixtures, get a nice mirror and distract the eye with some bold staging items (towels, rug, maybe a faux plant). 

That's the highest risk client we deal with, outside of trophy wives with excessive jewelry and lots of small dogs.Good investors understand that the cheapest contractor isn't likely to do the best job, and that the contractor who always tells you what you want to hear isn't really the one who's going to deliver your project on time.My company no longer does investor work, except for my own projects, so I'm not looking for business from anyone on here.

The other is finished with stainless appliances, granite counters, faux painting and decorator colors, wood or cork flooring, and ceramic showers.

One thing I have noticed however is that surface especially on the faux wood finishes can be very pores this can lead to difficult cleaning as far as paint clean up is concerned so use drop clothes.

In our older Queen Anne, Second Empire and Victorian vintage properties trim is frequently finished with shellac (or since coated w/ urethane), but where it is painted, the period calls for high-gloss.

You may be able to paint stone in a faux stone sponging technic that would not destroy value, but I wouldn't be brave enough to try.

I like building new, but we sell new, keep vintage rentals.

But, I'm glad vinyl siding is not used, as I do love to see the authenticity and beauty of vintage home brought back to life.

In Chicago there are many vintage units that are in high demand and everyone uses window units. 

But for something from around 1920, it may have already been refinished several times; I recently had 1920 vintage wood flooring refinished, and it does not look like there will be another sanding left ...One thing not yet mentioned is that 1920 vintage housing often used heart pine planks as the subfloor.