I have not towed anything behind my FW since the manufacture does not recommend it. On my last two trailers I have had a factory installed hitch on both to be used primarily for bike rack. After two trailer trailers close to 50,000 miles, and 4 bikes on the back no problems so far. I think if the tongue weight does not exceed 200 pounds or so, which that is what my hitches were rated for, you should not have any problems. But most states don't allow it anyways.
2012 Cedar Creek Silverback 29RE
2011 GMC 2500HD Diesel