We haul our bikes on a front-mounted hitch on a Swagman S64650 rack from etrailer.com. We have used the rack for 3 or 4 summers with zero problems. I like being able to keep an eye on them. I personally would never haul anything on the rear ladder. The ladder on our Pinnacle flexes quite a bit when my 220 lb. husband climbs on it. I would feel terrible if something fell off the ladder and caused an accident. Not to mention, in WA state you can be cited and face a stiff penalty for failure to secure your load.
On your truck bed question, we haul firewood in a large Rubbermaid tote in front of our fifth wheel hitch. It is secured to the front cargo tie-downs. Behind the hitch we carry our waste tote if needed, again tied down. We have had the tie down straps come undone because of the wind. I would be leery of putting anything behind the hitch that wasn't heavy and very well secured. I think you will be amazed how much stuff will fit in the cargo area of the fifth wheel. Everything else goes in there - table, lawn chairs, lawn games, coolers, etc. I don't worry about throwing dirty stuff in the cargo area either, as it is covered with a very durable material and can be mopped up or shop-vac'ed. And you are camping - things will get dirty!