2007 GMC Savanna CV 4.3l and GVWR Questions

One number you list is GCRW, I suspect you mis-typed, it's GCWR, or Gross Combination Weight Rating. This is the most your van plus trailer plus any and all passengers and cargo can weigh. If you subtract the van's GVW of 4700 form this GCWR of 9500 you are left with 4,800 pounds. This is all the weight you can add for passengers, gear, trailer, everything. I would guess that 2 people would weight at least 350 pounds so that leaves only 4,450 for the trailer and gear. If you can pack it lightly enough to stay within that then you are within your towing numbers. If carrying less cargo will get you there it should be fine.
Another thing to be aware of is the weight on the vans rear axle. This rating should be listed on the door sticker as GRAW. You will need to weigh the rear axle of your van with it fully loaded with passengers and fuel as you would go camping. Subtract the scale weight from the GRAW and that is how much you have left for tongue weight. Most trailers have around 13% tongue weight. So if you keep the trailer weight down to 4,450 that will be about 600 pounds of tongue weight. Your weight distributing hitch set up will add nearly 100 pounds so you need to make sure you have 700 pounds of additional capacity on your rear axle.