The manual is rather less than helpful here. There are five weight limits you need to keep track of when judging if you can safely tow something, and the manual only lists one of them.
- Gross Combined Weight Rating (GCWR): This is the total weight of everything: the tow vehicle and its cargo, plus the trailer and its cargo.
- Gross Vehicle Weight Rating (GVWR) for the tow vehicle: This is the total weight of the tow vehicle and its cargo, plus the Tongue Weight of the trailer. This can be divided into front-axle and rear-axle weight ratings.
- Gross Vehicle Weight Rating (GVWR) for the trailer: This is the total weight of the trailer and its cargo.
- Tow Capacity: This is the trailer GVWR that the tow vehicle can safely pull.
- Tongue Weight (also known as Hitch Weight): This is the portion of the trailer's weight that is carried by the hitch, rather than by the trailer's tires.
Your manual gives you #4 (Tow Capacity), and a hint at #2 (GVWR). Since a Dodge Caravan isn't designed as a tow vehicle, GCWR (#1) is probably simply the sum of the two. Similarly, the Caravan probably has identical front and rear axle weight ratings. You can probably find the trailer GVWR on a capacity plate somewhere on the trailer's frame or near the door, or in the manual. This leaves tongue weight.
Tongue weight is probably the hardest part of balancing a tow setup. If it's too high, it'll unload the tow vehicle's front axle, causing a loss of steering control. If it's too low, the tow vehicle will have limited ability to control the trailer's motion. Even if it's just right, it can overload the tow vehicle's rear axle, collapsing the suspension, giving a rough and possibly badly-controlled ride.
For American towing setups, the tongue weight should be between 10% and 15% of the trailer's weight; if this would overload the tow vehicle's rear axle or unload the front axle, you need a weight-distributing hitch (or a bigger tow vehicle). European towing setups generally go with a much lower tongue weight.
The rule of thumb for capacity is that the further under the limits you are, the better the vehicle's performance will be. For something that isn't designed as a tow vehicle, I'd try to stay under about 2/3 of the GCWR.