I can go through a 30 lb LPG tank in two nights fueling my heat, water and generator in those temperatures when boon docking, but my camper is larger with multiple slides. When on shore power, I use LPG as a backup but can run everything off electric.
Traction to get moving will be improved with the camper loaded but your braking will be less due to the additional weight. Like others have posted, you will find you need 4wd less with that additional weight over the drive wheels but 4wd does help with steering control on slick surfaces.