i prefer backpack mounted and vertically, better if its one that has the set up for holding a bow already but not hard to make work with straps and bungees. If you ride with a trailer, that would be the safest method of transport. I have also seen the quad gun mounts up front on the handle bars. In terms of not ruining your bow in case of wipe out there isnt many options other than a hard case. I consider having it on the handle bars the most risky of the methods.