[oldfielder]

The blue seas ACR basically has a lockout circuit that ties into your starting circuit/key switch and when it senses the voltage drop and ultimately spike of your motor's starting circuit, protects your charging end from the voltage swing Since many newer electronics are very voltage sensitive they will shut down when they sense the drop to avoid damage. You then need to restart them. Many contend that even with this protection, this process is hardly good for such sensitive instruments.
The Add a battery system from them basically gives you a tidy way to tie everything together, turn your battery system on, and go out and enjoy the day without worrying about it.
I have done a few of these systems and they are great, as are the tech guys at the company. They will hang on the phone with you and discuss any install issues with you and seem happy to do it. I am a fairly new customer of theirs, but I am very happy to plug their stuff.
If I were in your shoes, with the new boat, 100 bucks for the Add a battery and then a few more on wire would be my route. Nice new wire and you know your charging circuit is in great shape and down the road when you start craving fancy electronics-which you will-you will have a simple system.
I would keep the trolling motor setup just like you have it.
The best prices I have found for the Blue Seas stuff, btw, is a site called Inverter Service Center. They owner(forgot his name) of the company is a former marine tech, very responsive, and super helpful, as well. Give him a try.