From a strictly camping/hiking aspect, I would recommend a drop leg. With a crossdraw vest you are limiting your carrying ability regarding packs, not to mention adding yet another layer, unless you outfit the vest with other pouches to carry the majority of your miscellaneous camping gear.
Agree.
I've spent a good amount of time in the mountains, and accessibility and comfort are really hindered with a vest as it relates to packs and jackets. I always have a frame pack with me, and the straps interfere with access to the vest. Layers also need to come on and off (rain jacket), and I generally don't like messing with the rig that much.
I've used a thigh rig in this setting, and it has worked well, but it needs to be a good one so it fits both you and the firearm properly. Good fit can alleviate a lot of the wiggles/movement you mentioned. I'd actually rather carry the weight on my chest instead of on my leg, but it my experience the weight hasn't been an issue.
I've also rigged a standard OWB holster on the hip straps of my pack, and that works great, assuming you keep your pack on the entire time. Take it off to rest, and you've just lost access to your firearm.