This is often a complicated issue. Loaded weight (actual weight) is going to differ from vehicle to vehicle as it includes people, cargo, fluids, and any accessories or gadgets you install.
The easiest thing to do is compare the vehicle's Combined Gross Weight Rating (CGWR) minus it's Gross Vehicle Weight Rating (GVWR). This will get you close, at least close enough when comparing various models when determining which rig to purchase.
The CGWR is the weight that everything going down the road can be, including the vehicle, people, cargo, trailer, etc. Basically, if it moves when the vehicle moves, it is part of the CGWR limitation.
The vehicle's GVWR is the maximum weight the vehicle itself can be, including any people, cargo, and tongue weight from a trailer - but not the trailer itself. So it is basically everything but the trailer.
Therefore, subtracting the GVWR from the CGWR, you get the nominal trailer towing capacity.
For the 34.2, it appears it is built on a 22,000lb chassis (the GVWR), and has a CGWR of 26,000lbs. At first glance then, the allowable trailer weight maximum will be 4,000lbs.
However, some people "borrow" unused cargo capacity to add to the trailer weight. If the total vehicle weight + people + cargo + fluids is appreciably less than the GVWR limit, they take that "excess" capacity, and add it to the trailer capacity.
This is the complicated part. Mathematically it keeps you under the CGWR, but there may be other factors to be considered that may or may not make this a good idea. It all depends on the manufacturer's recommendation.
Of course, at minimum, to borrow any excess capacity, you have to to determine the vehicle's true loaded weight with people, fluids, and cargo by weighing it.
For example, between the holding tanks and fresh water tanks, you can haul 180 gallons of water in the 34.2. This can add a significant amount of weight to what your vehicle is hauling, almost 1,500lbs. By emptying these tanks before hitting the road, you can reduce the hauled weight signifcantly.
If you intend on staying mostly at improved parks with full hookup (sewer and water) you don't need to carry much water - perhaps 20 gallons for use between campsites. If you are boondocking, fill up your water and empty your holding tanks just before camping.
Also, many suggest subtracting at least 10% from the vehicle's CGWR as a "do not exceed" weight as a safety factor (personally, I go 25%, but I like to err on the side of safety).
The only thing that works on a RV is the owner...