To get weighed, go to any truck stop with a scale. Check CAT Scale | Network of Certified Truck Scales.
for a location near you. When asked for your rig number, tell them private vehicle. Then pull around and pay. I usually weigh the truck front axle on scale pad 1, rear axle on scale pad 2 and all trailer axles on scale pad 3. I then pull into a parking spot and unhook, go back and weigh just the truck (same scale pads as before). Typically first weigh is $9-12 and any reweigh in a 24 H&R period at the same scale is $1-3.
If you are attending the factory rally, there has been a company that will weigh each individual tire for you in the past. I am not sure of cost or if they will be there this year.