Success! I was able to run the cables without too much trouble, thankfully I was able to re-use the existing cable-runs from the old Simrad Autopilot that I had installed here earlier:
1. I installed the fluxgate compass in the same location as the Simrad’s compass, in the first step under the stairs going down to the galley:

Fluxgate Compass Install Location
It has to be located away from the engines (and any ferrous objects), centerline on the boat, low in the vessel, and it must face to the bow.
2. I then ran the wires through the engine room, wiring tying it every 3 feet to the walls/bulkheads.
3. I attached the new wire (5 mini wires inside) to the old Simrad (3 mini wires inside) with duct-tape and some grease, and then went to the bridge to pull the wire up to the helm where the computer is located.
4. I installed the rudder indictor per the instructions (make SURE you line up the two lines on the backside of the rudder indicator once it is attached and the rudders are in a neutral/straight):

Rudder Indicator installed
5. I repeated the process of running the wire to the helm as I had done for the fluxgate compass
I was able to re-use the existing 12v pump for the hydraulic steering which saved me a lot of hassle. I just hooked up the wires to the computer, along with the fluxgate compass, rudder indicator, ST6001 Display, and the NMEA wire from my Garmin 2010 .
All worked as expected; I did the calibration to set it for a planing hull and pump type, and I did do some fine tuning for the rudder indicator. Tomorrow I’ll take her out into the bay to do the sea-trial calibration (set the deviation for the fluxgate compass and then do some navigational tests).
The Garmin unit worked perfectly with the SmartPilot! I put in a waypoint, and you can see it reflected on the SmartPilot display “DTW” means Distance to Waypoint:

SmartPilot display, showing DTW from the Garmin GPS
Here is the Garmin screen as a cross reference:

Garmin GPS screen, notice "To Dest" box showing 2.5nm
Information on the sea-trial to come tomorrow.