You might contact
RV Safety (aka Aweigh We GO) and ask when they will have a weighing team in your area. They give an excellent written analysis of your weights and tire pressures as well as raw 4 corner weights.
Big RV dealers have sometimes invested in 4 corner scales - you might call Beaudry and see if they have them.
If you can find a scale that isn't busy, you can usually do it yourself by driving half off/on a scale that isn't raised much above the surrounding ground.
You can get axle by axle weights (sufficient, though not optimal) at many truck stops. See the Cat Scales web site for locations near you. Flying J's also have truck scales. Usually axle weights are sufficient unless you find you are near a crossover pint in the weight tables. Even then you would just assume the next higher level. That's sufficient to cover any imbalance in the side-to-side weight, You don't want to figure the tire pressure that close anyway - err on the side of too much - go 5-10 psi over.