You may not be able to weigh all 4 corners, but, if you go to larger recycling yards you can weigh your vehicle there for free, if you are nice to them and they aren't busy. If you can get each individual axle weight, you'll probably be OK. Some California Highway Patrol officers have mobile scales for truckers in the back of their vehicles, but, good luck finding one who will cooperate with you. Utah has instant readout axle weights in their weigh stations. I've driven through those several times with my Class A and they didn't seem to mind.
Chum lee