I towed with my old SRW 1 ton about 60K miles with 35 foot double slide challenger. It hit the scales at about 13,000. I stopped by a Cat scale and I was within all tire and and axle weights. Total was 21,400 combined.
It towed OK, I had plenty of brakes. But, when a truck would pass me I could feel it push and then pull me. Also During high side winds I had to really work to keep it straight. I hit water standing in VA once at 65-70 mph and thought I was going to loose it. A dust devil just north of Vegas knocked me across two lanes and again I about lost control. The other 10 years of towing was fine. I did have a supercab long bed, and yes the longer the tow vehicle the better. I felt I was safe and towed mountain passes just fine. I lost a rear tire on the truck once, and had in been on say the WV turnpike I might not be here today.
Even though I love the look of the new trucks and 20 inch wheels I love my DRW and how well it tows, the extra margin of safety for the once every 5 year or 30,000 mile instances where the******hits the fan.
Now hitting the scales at 29,040 and a 38 foot rv I wouldn't want a SRW truck for a rig that size.
Think about this, road construction, two lanes with concrete barriers on each side, the lane shifts across the median, with a tractor trailer beside you. The roll at pitch of the road will cause the SRW some issues that might be just enough to rub the side or trade some paint. I wouldn't pull my current rig on a smaller truck, the above happens all the time, to me anyway and the thoughts of it on a SRW gives me white knuckles.
If you plan on towing a lot, get a DRW, it's just set the cruise and drive with one hand, or one finger if you want. Sit back and enjoy the drive.
Or you can buy a SRW, fight the wind, the trucks passing, pitch and roll of the road, maybe you'll never have anything other that long stress filled days, or maybe not.