Where does one find out the wet weight of an RV?

in addition to the gross weight sticker items you mentioned, motorhome mfgs also provide a CCC cargo carrying capacity, and UVW unloaded vehicle weight(includes fuel, coolant, oil). Many times those are on a separate label glued inside one of the interior cabinet doors.
So the only other "wet" load is how many gals you decide to carry in your water, waste & propane tanks. that's controlled by you, not the mfg and should be calculated as part of your "cargo load".
most liquids weigh about 8 lbs per gal, and propane weighs about 4 lbs per gal.
Since the published CCC and UVW are based on avg assumptions and usually exclude any vehicle options, its always required to weigh your rig at a certified truck scale to confirm.
as for your toad size limit, that's usually controlled by the MH hitch rating. I've never seen a MH hitch rated high enough to allow you to exceed the GCVWR.

No matter what you find or who owns it, I would require that prior to purchase you be allowed to weigh the coach. If the fresh water tanks are not full then add 8 pounds per gallon that needs to be added and 7 pounds per gallon for diesel (6 pounds for gas). In theory, as you empty the fresh tank you fill the black and grey so it's generally OK to use the weight with the black and grey empty but leaving a bit of a fudge factor is a really good idea.

Who has the rv, used, new! There should be a sticker in the rv which shows the weight as it left the factory with full fuel but empty tanks. From there you can make a better decision.

That is a great suggestion, but here is my problem. I do not own the RV. I have all the gross rated numbers, but I don't have the real weight of the coach. How can one find out how much a coach weighs. And thus make some important calculations on what size toad I need to buy and how much stuff I can load and still be with in the rated limits. I don't want to buy something only to realize what I want to do with it cannot be done. Know what I mean. Thanks

Fill the tanks, load with the people going and take it to a weigh scale.

I chose to fill both waste tanks and the fresh water tank for a "worst case" scenario.