We all have gone through the process of figuring out what can my tow vehicle REALLY tow. There are the numbers, and then there is the truth. Its really just a******shoot, with in reason, isn't it? I j...
Sadly what you have is a rather large grocery getter. What you need to do is find the GCWR figures from the GM web site, Then load everything in it including passengers you would have for a trip and go to the scales. Subtract your scaled weight from the GCWR. That is the maximum weight trailer you can comfortably tow. Don't even think about a fifth wheel, get a TT instead.