This is what I do, works great , until batteries loose power, but you should have 6 hours of good trolling before you have any issues with battery life. It only really stuggles if the wind and waves kick up. On a nice condition day, battery life is not an issue at all.garmin tr1 gold is a stand alone kicker autopilot, runs as much as a brand new outboard, this is why i have an ez-steer for the time being.
now if you have a boat with a shorter gunnel to water dimension were an electric trolling motor could be used on your bow , an i pilot could be used to steer your craft while under power from the kicker.