This is what I have and I really like. Held my bike rock stable and I would trust it for distance travel.

Swagman XTC-2 a 2 bike platform carrier. Got it at my LBS.

http://www.etrailer.com/Hitch-Bike-R...an/S64670.html

With the bikes off the carrier, you can access stuff in the back of your vehicle, which also would be handy.