Gotta do the math on this one, brother- IMO the numbers don't add up to a safe trip for you.
The Gross Combined Rating for a 9-7x is 10,500 lbs. The trailer and load is at 4k lbs.
Figure 4800 lbs curb weight for the Saab, then add the weight of all passengers, fuel, cargo, and tongue weight. Max Gross Vehicle Weight Rating is 5950 lbs (GVWR includes all the factors listed in this paragraph).
With the above, you're right at the edge of the capacity of the Saab. If you're like most of us humans, there will be another 500-800 lbs of "stuff" not accounted for between the tow rig and the cargo trailer.
If you decide to go for it, I highly recommend you ensure your tires, braking system, suspension, cooling system, etc are gone over with a fine tooth comb before you hit the road.
A one way rental of a cargo van is the better alternative.