Without knowing what the components are, I would say around $10. Many of these older bikes are stripped and made into single speeds or fixies now. The rear dropouts are great for that. I see the frame is fully lugged but what is the tubing? There should be a decal saying what the tubing is. The cheater brake levers and stem mounted shift levers usually indicate this as an entry level road bike in its day and not a bike with high end components. The frame can still be a quality frame though. I purchased a Vista with a cro-moly frame last year for $2 that is basically set up similar to your KHS. I plan on turning it into a single speed.
The desired frame sizes should fit someone 5' 11" to 6' 2" or larger. This works out to a 23" or 25" frame. Smaller frames are not in as of a demand.
I see people are asking $15-$160 for KHS Winners depending on condition. Some have swapped out components so they are not original.