I'll try to add to the "towing" issue as we regularly tow with a PW Lexor (roughly equivalent to the RT 190), though I do understand this posting is about a RT 210.
The GVW of a Chevrolet Express is listed as 9,600 lbs. RT's info indicates the GCVW is 16,000 for both the 190 and the 210. So, based on those numbers alone (assuming the RT is loaded to capacity) the max towing is 6,400 lbs.
But, and there are a number of buts.
The chassis frame of the 210 is extended a bit (about 18 inches I think) as compared to the 190. That alone complicates things as the distance from the rear axle to the hitch ball is longer. Shorter is better.
The hitch that is used is, in fact, rated at 10,000 lbs (a class IV hitch), even though you can't (shouldn't) tow that much. And, since there is a hitch, the bare unit usually comes from the factory "pre-wired" for a brake controller, though none is factory installed.
But, and here's the real but, the rear tires are rated for only 3,024 lbs each when inflated to 80 psi (the max inflation pressure), so the real Achilles heel is not the trailer weight, nor the hitch capacity, but rather the weight on the rear axle - 'cause loading it to more than 6,000 lbs. is just asking for trouble.
If one assumes that a "good" tongue weight is 10% to 15% of the trailer weight (I use 12% as my target), then pulling a 10,000 lb. trailer would mean that one has "added" 1,200 lbs. to the hitch ball. (RT indicates a max tongue weight of 1,000 lbs. which is the maximum tongue weight on a class IV hitch).
In our case, we regularly pull a roughly 3,200 lb. trailer (single axle, 12', "V" nose, with rear ramp for the motorcycle) so I "figure" about 400 lbs. of tongue weight which is "carried" by the rear axle within its 6,000 lb. limit (remember the tire limits).
The longer distance between the rear axle and the hitch ball on a 210 only exacerbates the weight transfer problem (from the trailer to the rear axle).
When I did the calculations about towing before we bought our PW (about five years ago), it became very clear that we could not tow our 3200 lb. trailer with a RT 210 AND be within all specs - GVW, GVCW, rear axle load weight, etc. - and I was unwilling to start from a position of being overloaded from the first mile. A RT 190 would work, if properly equipped, and in the end we just liked the layout of the PW better.
The other things we needed to consider and address were a brake controller, auxiliary ATF cooler, and a few other things. To date, we've towed around 30,000 miles and been comfortable doing so as, I think, we did the arithmetic, honored the "limits" (every one), set it up correctly, and we slow down recognizing the additional weight.
In short, if I saw a RT 210 towing a 22 foot trailer, I'd get out of their way as quickly as I could 'cause they have to be way overloaded.
But, I do know folks do it almost every day.
Cheers.
