It all depends. The best place to get your coach weighed is at large rallies. RV Safety is usually at large rallies. Go to RV Safety, Merritt Island, Florida
to see what their schedule is. If you go to Flying J, Pilot or other truck stops, they have scales. These scales are made for axle weighing. To weigh four corners you'll need to find one of these scales that will allow you to pull on the scale like a truck (get axles weight) and then pull on a second time with either just the left or right wheels on the scale. Sometimes you can to this and sometimes you can not. Once you have the one side weight, you can subtract that from the first weighing of the entire axle to get the other side wheel weight. Depending on the height of the scale above the ground, there will be a slight distortion of the weight due to the angle of the coach. The flatter the better, for the second weighing. This should get you really close to what your four corner weight is.
Over four years, my coach gained 2K pounds of weight
. I'm still trying to determine where that weight came from and what I can do without. The coach is well balanced and I am under my GAWRs so their is no safety problem. I just do not know where one ton of stuff is that wasn't there 4 years ago.