With only 3 inches out of level...don't worry about it and enjoy camping!! Unless your anal like some are about your camper being level, drop your hitch on your camper to get you 6 inches of clearance on your truck bed and go. I've been over 4 inches out on my toy hauler empty and a bit more with both Harleys in it and have had no issues at all with frig not working or with too much weight on rear axle. There is an equalizer between your axles on the springs if you have leaf springs that take care of having more weight at the rear or the front by equalizing the weight between the axles. If you have a torsion susp then you don't have the equalizing between the axles. Weight could be checked by weighing the camper only when hooked to your truck and then pulling forward until front axle of camper is off of the scales and check your weight then. Subtract that from your combined axle weight and that will tell you what your carrying on the camper front axle. If the rear axle is loaded much more than front then you might have to raise your camper some. If in my opinion if its 500 lbs or less different I wouldn't worry as long as your tires are rated to handle the weight.
