The ST4000 only allows input over NMEA0183.
Output is over SeaTalk1.
You should be able to do everything you want over SeaTalk1 using a Raymarine
1 to SeaTalkng(NMEA2000) Converter Kit and a Raymarine
A06046 SeaTalkng to NMEA 2000
Or if all you want to do is send track data to the autopilot you could use the Actisense NGW-1 or the Simrad
AT10 with a Simrad
The Vulcan uses the standard NMEA2000 connector not the old SimNet connector.
If you use the Raymarine setup mentioned above you will not have to build a NMEA2000 Backbone. If you use the Actisense or Simrad setup you will need to build a NMEA2000 backbone.
Therefore the best and cheapest option is to use the E22158 and A06046. Not to mention this option is simply plug