80 pound Minnkota AP with co pilot on a quick mount, half the cost and ready to go. I would then learn to come back to the dock on the Minnkota only and use it to dock, You could actually leave it in the vertical position pulled up to the stop, outside the gate and it would never be in your way. You would just drop it down in the water when you want to use it.
In theory the iPilot version of that motor has GPS and could learn a route to dock the boat and do it for you. I have the motor I described above with the factory iPilot option and I would not trust it to do the job automatically on the iPilot, but I'm sure it would work to get the boat into a slip running it manually.
I am thinking about going back to fishing from the pontoon and will move the Minnkota to that boat. I'm completely confident that the 80 pounder will provide plenty of power to move my 20 footer around. I have had 55 pound Autopilot motors on 20 foot pontoons before and they have enough power to push a smaller pontoon around.
Even if you must have 100 pounds of power I would still go with a trolling motor, with remote control on a quick mount bracket at the front gate. It gives you what you need out of the box without having to figure out how to mount and control the drive mounted motor.
