I like this idea. We have a 10’ box Starcraft like yours. Do you have more pictures and with close ups? - Has the roof indented from the rear tires bouncing? I could see using a 4”x6” piece of wood w/ a padded bottom and Velcro strapped to the tire. - I really like the idea of the front forks bolted to the DIY front mount. More secure -and- lowers the bikes wind resistance and clearance 10-12”! - Did you consider a solid turnbuckle side attachment instead of (somewhat) flexible straps? - do you have pads under the front 2x4’s? - Have you made any revisions since your April 2019 post? I am excited about this option. I look forward to whatever you can share.