The key thing about the Electra Townie and bike carrier racks is not its weight--although that's considerable--but the swoopy sloping top tube. It's not really going to work well on trunk racks, which are designed to hold the bike by the top tube. Or even hitch racks that hold it by the top tube. Yes, with adapter rails and futzing, it can be made to work, but life's too short.

You need a rack that holds it by the wheels. Given the gravity in Townies, hitch racks are your best bet. This past spring I bought a Yakima Holdup. Saris, Thule and others make essentially similar models. I was able to get a better deal on the Yakima.

There are cheaper models out there, but this type of rack seemed to be right for me. It's easy to use, folds up out of the way when the bikes are off, and of particular note, you can lock the rack to the car, and lock the bikes to the rack, which is handy when stopping to eat on the way, or on the way home.