I would not use the safari as the tow vehicle for a 31 foot airstream. Even if the weight ratings are as close as you state. The weight of the tow vehicle, ponies under the hood, as well as the wheelbase make a tremendous diffrence in towability, handling and safety. based on a 95 model the van itself only weighs 3988, with a cargo capicity of 5950. I will admit that 1962 Pounds seems like alot but that needs to include you, yourFriends/family, The dog, gear, gas, and the 800 lbs of tounge weight.
I have seen smaller trailers and boats pulled by a safari, but I would not reccomend it. I have seen trucks in my region that would be capable haulers of your trailer in the 6-7K range that are 6-7 years old.