THANKS ALL! Very encouraging! So from what I gathered, I can just yell back to her "shut up and pedal when I pedal"
I will definitely try on my own before trying with my wife. I am used to the length because of the trail-a-bike and the tandem trail-a-bike I've towed my kids on. But even with the double trail a bike, the weight of my two kids was only about 80 pounds. I've also been reading up on tandeming techniques. The one thing I won't do is put on my clipless pedals right away- I think I'd rather waste a little energy than have both of us fall over!
Now to find a tandem! Craigslist here I come!
Thanks again all for the helpful advice.