Gravel pits usually have scales. Mine has always let me use it for free as they appreciate my attention to safety on the road.
I take the following measurements:
1. Base camper weight - camper only (un-hitched from tow vehicle) with the usual gear loaded inside and full water/LP tanks. This will indicate if you're within the camper's GVWR.
2. Camper axle weight - same as #1 above, but with the axle on the scale and the tongue (jack) off the scale. This will indicate if you're within the camper's axle rating. You can also deduct this amount from #1 above to calculate your camper's "tongue weight."
3. Tow vehicle + camper tongue weight - camper hitched to tow vehicle with both tow vehicle axles on the scale, but the camper axle off the scale. This is the base weight of your tow vehicle plus the tongue weight of the camper.
What I like about this approach is that subtracting #3 from your tow vehicle's GVWR gives you a leftover payload capacity for passengers and gear, all of which can be easily weighed and tallied at home as you pack without revisiting the vehicle scale.
In addition to being safe, the little spreadsheet I maintain helps talk the wife out of overpacking
Over time, I've been able to redistribute some items inside the camper to lessen tongue weight and let the camper axle carry these items for me to free up payload capacity on my tow vehicle. Of course I still keep tongue weight at 10% or more of total trailer weight.
I also weigh the front and rear axle of my tow vehicle to make sure they weren't overloaded. The front is easy (park the front two tires on the scale and the rear tires and camper off the scale). The rear axles require some math to obtain a calculated number since the vehicle scale is often too large to only include the rear axle of tow vehicle.