Can your wife put her bike onto the roof by herself? Assuming she wants to ride by herself. IMHO roof racks are a pain because you have to lift the bike onto the top of the car, with a minivan or SUV, the roof is even higher. I have used a trunk mount, a cheap one I found during our town clean up day, for several years, and several different cars. I have never had a problem. Just use you head when you put it on the car, and when you put the bikes on it. The down side is if you have some sand, or other grit under the pads, it will scratch you paint. I have also used a hitch rack, my favorite, if you have a receiver hitch. Also the two most popular brands, Yakima and Thule, are overpriced, again IMHO. You can get a good secure rack for less, shop around, and check eBay.

And, from the bottom of my heart, THANK YOU!