I just purchased the Toad supplies to tow my Grand Cherokee. I was going to buy the Brake Buddy (in fact did, but canceled it) in favor of the SMI which is on sale at PPLMotorHomes.com for $759 (Normally sells for $1,300). From what I read and heard, it's the cat's meow in brake systems. I'm anxious to try it out. There are a couple of great things about it. It comes with the breakaway and a remote. It uses the power brakes of your Toad. If you've ever tried to stop a non-running vehicle without power brakes, you'll appreciate this system.
As for putting the Transfer case in neutral. The owner's manual will tell you all about it if they do as good a job as Jeep.
As for your other questions, I'm not knowledgeable about Nissan. Had one once, long time ago. I prefer the Jeep. We're going to get a Liberty 4x4 in a few months.
<font color="#0000ff">George Eldridge