I'm planning to install a hitch and then use a hitch-mounted rack to carry my family's bikes. I could barely fit my bike into my former Explorer, so I doubt that anything other than a child's bike would fit comfortably in the Escape. Also, as you mentioned, you have the debris to deal with if the bike is inside the truck. Roof racks have issues with accessibility (unless you're tall and have a very light bike) and there's always the problem with the garage door removing your bike if you've forgotten it (also the occasional low tree branch or overhang). The weight penalty for a hitch would be minimal (it probably weighs less than a full tank of gas) and there should be no drag penalty from having the bike behind the vehicle as this is all turbulent air anyway. This also prevents scuffs on the finish as neither the bike nor the rack touch the paint. You'll have the additional costs of the hitch and the new hitch-mounted rack, but you've got to spend the money you're saving on gas somewhere.