As others have said, get some practice before you take your wife with you.  Find a big open parking lot and spend an hour.  The type of stuff you learn in the MSF course.  Low speed handling, then put your wife on the back and do the same thing.  It might be boring, but the last thing you want is a suprise with your wife on the back.  It's ok to make mistakes, but make a mistake in front of your wife and guess what she'll remind you about for the rest of your life.  And that's if a scar it's involved.    Would kill me.

Well, you do have to look around pretty hard and find a parking lot with no borrow pits, hills and corners, dogs that chase you out of adjoining trailer parks, traffic (both oncoming and tailgating) logging trucks whipping around and dropping bark on you, etc.  But IF you are able to find such a parking lot, it should be as good as a nice, safe, public roadway to learn on.