I wouldn't do it...the Dakota suspension is not rated to handle the weight of a fifth wheel trailer. I would need to look up the exact tow ratings, but from memory , it tops out around 6000 lbs...a fifth wheel usually exceeds that by far
In light of that...2000 lbs should be no problem. To be honest, I have never heard of putting a fifth wheel in a dakota, but you are well within the tow rating so it won't be a problem. It is actually better to tow from a fifth wheel then the reciever off the back. It distributes the weight much better.