I would do as others above have suggested, add the DCS system and try it out first before re-wiring your layout. It might just work as it is and may not be as difficult as it seems? As others have said here, theirs worked without having to do a lot of changes.
If you do have problems, I have found that the addition of blocks made the biggest difference in the operation of my DCS system. Before my current more permanent layout, I had a few temporary layouts using DCS on which I never bothered to add any blocks. They all had problems here and there. They were not large and I was still able to get things working for the most part.
My current layout from 2014 has blocks and I have not had any DCS problems at all since I got it up and running. But, I did things a bit differently, I had DCS first and wired for it using blocks as recommended in Barry's book, then added Legacy a couple years later and it all works well together.
