I'm no expert in this but I have a bunch of conventional engines I was looking to control with a cab-2. What I have settled on is that the easiest, and probably most expensive, route is to buy a ZW - L. Then you can connect the legacy base to that and address the tracks to control via the remote.
That doesn't help you since you have a cab-1 already but thought I'd chime in. I'm interested in what others say since I'd like to make this switch too. I'm hoping others have cheaper alternatives.