I agree with the above comments. Doing all five days can be A LOT even for a hardcore car guy. Your wife might not appreciate that. Best bet might be to pair up with another couple that your wife gets along with really well so the wives can do their own thing if they want and maybe just plan on doing the first couple stops and playing it by ear after that. You won't get a nasty call from the Power Tour director if you don't show up at a stop.
The cool thing about Power Tour is you can do whatever you want. Want to just go to the first day and go home? Okay. Want to take their mapped out route? Okay. Want to take your own route? That's fine too. Want to skip a day so you can meet up with friends somewhere else and catch up at the next stop? Go for it. Want to just check in first thing and explore the city it is in rather than hanging out at the show all day? Cool.
The last time I went, it started in Cleveland and went to Kalamazoo. One of my buddies from school flew in from NY. We left Grand Rapids, drove to Cleveland, met up with our other friends from South Carolina and walked the show. Normally I can go Grand Rapids to Cleveland in four hours flat so Cleveland to KZoo should be about 3.5 hours. It wound up taking about 7. I get it, they take you through smaller towns and generally stay off of major interstates. People will line up along the route and just plop down chairs and watch cars go by all day. When we got to the lunch stop at Toledo they were out of food. No big deal. The drive took so long that by the time we got to KZoo the show was already closing down. Also the fairground there is one way in and out so just getting in took about 45 minutes. I was pretty salty for a while after that, but I got over it. I can't imagine the amount of logistical planning needed to pull off an event like this.
If you are into cars, I think it is worth trying out at least once if only for a stop or two. I don't think you will regret going. You will probably be the only SuperCoupe there too which is cool.