RE: Weight (load) Distributing Hitches
What do the weight distributing ball mounts cost/run?
The cost will depend to some degree on the manufacturer of the ball mount and the depth of the drop that is required for your application. The link below will take you to one of the on-line catalogs that offers Reese Ball mounts.
Reese Weight Distributing Adjustable Ball Mount
In addition to the weight distributing ball mount, you will also need the spring bars that Reese calls "Trunions", and a set of "snap-up" brackets to mount on the trailer tongue. The links below will take you to these items from one of the on-line catalogs:
Reese Trunion Style Hitch
(I am not certain from the description, but I think that the above item includes the ball mount but not the draw bar itself.
Reese Snap-Up Brackets for Trailer "A" Frame
(The illustration at the link above actually shows a Reese Dual Cam setup as well as the Snap-Up brackets which are the balck devices on the hitch that the chains are attached to.)
It is probably fairly evident from the above illustrations, but the ball mount will slide into the receiver on your Suburban and lock into the receiver with a special heavy duty pin (usually included with the draw bar/ball mount assembly when purchased as a unit). The trunion bars then slide into the ball mount one on each side and the trunion bars are then attached to the trailer via the snap-up brackets.
The one difference that you may encounter is the Reese Dual Cam Sway control. It was popular with many previous owners of Vintage units, and many of us continue to use them. I personally love my Dual Cam Sway control - - it is only very marginally more expensive than the friction devices and is far easier to manage - - requiring no constant adjustment as the friction devices can require under certain travel conditions. The Reese Dual Cam sway control system mounts on the "A" frame of the trailer hitch and can be seen in the illustration with the snap-up brackets - - it is the device with what appear to be large "U" bolts with metal "saddles" that the trunion bars ride in. In my experience it has performed flawlessly once properly setup, and I wouldn't be without it on any trailer with a loaded weight in excess of 4,000 pounds.
So far as installation is concerned, this entire setup can be handled by an experienced do-it-yourselfer. I like the additional security of knowing that all adjustments are absolutely correct, so I have had my Airstream dealer set up the equipment on my trailer and tow vehicle. The instructions that Reese provides with these products are very detailed. My concern has been with getting the ball mount at the proper height and angle - - prior to having my dealer setup the entire system, my trailer hitch installer supposedly adjusted the hitch to the proper height and angle - - turns out he didn't follow the instructions from Airstream and the hitch was far enough out of adjustment that the trailer did not track properly behind the Chevy pickup that I was towing with at that time. When the hithc is properly setup, you shouldn't be constantly reminded that the trailer is behind your Suburban - - in fact within a few hundred miles you might find yourself looking in the rearview mirror to verify that the trailer is still behind you.
I had another thought while keying this response. You didn't mention mirror extensions for your Suburban. Unless you happen to have one of the units equipped from the factory with the adjustable Westcoast mirrors, you will likely need some kind of mirror extensions for either the TradeWind or Overlander. There are two or three types out there, and each person develops a preference. I happen to have two styles, the slide on type:
SIPA Slip-On Towing Mirrors
I have used these for the last three years, and they are adequate. Ideally, they need about 2" more reach to really serve the intended need.
Two years ago, I acquired a set of clamp-on style mirrors that I really prefer made by McKesh. They are rather expensive - - something in excess of $80.00, but they are fully adjustable so you can get the best view possible.
McKesh Adjustable Towing Mirrors
RE: Trailer Tow Package on '99 Suburban
Basically the trailer tow package on the '99 Suburban included an auxiliary transmission oil cooler, a motor oil cooler (at least on 2500 series), heavy duty springs, heavy duty shocks, a hitch receiver, heavy duty alternator, heavy duty turn signal flasher, trailer wiring harness, <a notation on my invoice says heavy duty cooling - - I don't know whether that included an upgraded radiator, but it did include the oil cooler and transmission fluid cooler>, heavy duty battery (factory suggested option).
Good luck with getting your rig setup. It can be frustrating at times, but it will be worth the effort.