Hydraulic to mechanical conversion - cable routing A family member has asked me to convert their hydraulic disk brake system (an old Hayes So1e) to cable disk brake. I believe the bike is only going to be used casually, so performance isn't paramount, it just needs to work.

The image shows the hydraulic hose for the rear brake running along the middle of the top tube. What would be the best way to implement a cable? The tube is slightly square shaped, so I think it would be difficult to fit a clamp-on cable stop (and would also interfere with the gear cables). If I omit cable stops, use uninterrupted housing for the whole length and use zip ties to secure it to the frame, I'm thinking there might be issues using barrel adjusters.
You can run the cable outer housing exactly the same as the hydarulic hose. 

The main reason for using frame stops is to provide sections that don't suffer from compression of the outer housing under load.  A full run of brake housing could compress and use some of the braking power.

You could solve this by using compressionless brake housing, which has multiple metal bracers instead of a continuous coil.

NOTE I am NOT suggesting to use gear housing as brake housing.  They're different thicknesses.