In our research to select the right bicycles for campgrounds and trails, we were advised on a mountain bike forum by a bike mechanic that carrying bikes on the back of an RV is not very good for them. Many of the bikes he fixes from RVers are in the worst condition of any he sees, due in part to water being forced into every nook and cranny at highway speeds. I've thought of covers, but they'll probably get ripped to shreds in no time unless we can find some designed to withstand 60-80 mph winds. Most of them are intended for covering a bike in your driveway or on your balcony to keep dust and rain off it. We have a 36' 5er with 3 slides, which occupy most of the interior in travel mode. Besides, I'm not sure I want two more potential projectiles riding in the trailer. Our truck has a RollNLock tonneau cover on the bed that can be locked at intermediate stages. In other words, it would be possible to create a somewhat "weather resistant" compartment forward of the hitch. This would require the bikes to lie flat though, and I cannot find any truck bed "bike rack" in this configuration. All of them support the bike vertically. How does everyone else transport their bikes? What tricks have you learned for keeping your bikes protected? Has anyone seen or heard of a bike rack designed to carry two bikes horizontally under a truck bed tonneau?