Actually, I did research the links. I was having a difficult time initially trying to find the site with the curb weight calculator. It is very detailed offering the ability to input your exact build codes which is very specific to exact configuration. Thanks to all those who posted the links and excerpts.
I believe I was able to estimate the weight pretty accurately and also confirmed my estimate using the Payload less GVWR method. (interestingly, my van had a modification to it that added 45 lbs to it prior to my purchase and is reflected on the GVWR Sticker with amendment) It is not likely that I will be re-weighing the van soon but by estimating the weight of passengers in the van and other items including the added hitch when I weighed it as a combination. I believe that I am within 100 lbs of the actual weight of the unloaded van. Should be interesting to find out some time how close my estimate is. By my estimate, the tongue weight of the trailer is just under 10%which may help explain some handling issues that were occurring. I would like to see closer to 12%. Also interesting to note that I have owned this trailer for 8 years and had the estimated weight accurate to within a few hundred pounds all this time.