Hi Jim
I am not qualified in any way to answer your question I am young (76), I don't have a 7687 but a DigitalBahn DSD2010 instead but I have a CS3 and 7286.

Here are a few thoughts about your question;
- the CS3, among plenty of other things, is capable of issuing the exact same commands as from a Keyboard positioned to address 225.
- if it is of interest you may have a CS3 screen to represent the same key layout as on the keyboard.
- with the CS3 you will have all the fonctionalities you had on a 6021+keyboard.
- having a full automatic operation similar to what you have in Rocrail is restricted and a bit problematic (certainly as it was before on the previous set_up). This is because to handle long locos on the bridge, it is better to have more than one detection zone on it (I have 3 in the video below).
- programming of the 7687 is made with the virtual keys, exactly as they were on the keyboard (less than 5 seconds to enter the programming mode, etc)

Here is my 7286 with its DSD2010 decoder in operation with Rocrail in a totally automatic operation

I hope this can help you somewhat.
Cheers
Jean