We haul our campground bikes on a rooftop carrier, but thru a rainstorm or near the coast you've gotta fight the rust. I don't know if this'll work for two bikes, but seems to be OK for one?!
I welded a 'post' on the ball mount of the WDH for the bike rack to slip in to. Removes for access to the rear hatch. :)
<img src=http://www.fiberglassrv.com/board/uploads/3ec6a89ca9c23Casita bike 1.JPG/>
<img src=http://www.fiberglassrv.com/board/uploads/3ec6a8ae43b74Casita bike 2.JPG/>
<img src=http://www.fiberglassrv.com/board/uploads/3ec6a8c7a483aCasita bike 3.JPG/>
<img src=http://www.fiberglassrv.com/board/uploads/3ec6a8d9433d0Casita bike 4.JPG/>
<img src=http://www.fiberglassrv.com/board/uploads/3ec6a8fb981d8Casita bike 7.JPG/>
<img src=http://www.fiberglassrv.com/board/uploads/3ec6a92128891Casita bike 8.JPG/>