The towing specs are in the Roadtrek brochures for the year, 1997 here.
That said, they are at best guidelines as they are quite high for the real world.
The important one is the GCWR which is what the trailer and van would weigh together. You would weigh the van with everything in it including passengers and water, supplies, etc. and subtract it from the GCWR to get towing capacity.
The next rating isn't shown but should be on a sticker on the van, and that is the max weight allowed per axle. When you get weighed you will have both the front and rear weights listed, so you need to make sure your tongue weight doesn't push the rear axle over allowable.
Once you know your tongue weight you add it to the weight you got for the van to make sure you are under the GVWR which is the total allowable weight for the van.
Note that the rating on the hitch means very little in all this, as it is only the rating for the hitch and has nothing to do with the van's capacity. It just needs to be big enough to cover the van's capacity. Many times the hitch is rated for much more than the van can handle.
Then you get back to the real world and find out the long overhang of the Dodges makes them squirely with bigger trailers and more prone to going overweight on the rear axle. Heavy trailers need brake controllers in the van, you might need trans and oil coolers, rear airbags, etc. This stuff is all needed to go to max towing in most cases.
Hopefully, someone who has a Dodge and has towed with it will be able to give some real world experience. My guess would be that 2000-2500 would be reasonable for a mostly stock Dodge class b, but might require a few things like airbags in the rear.