Hi and welcome to the forum first.
I have to agree with the other here that state, you can not pull a 5er with that model of pick-up truck. I checked the Dodge Body Builder .com Web site and I could only find information from 2004 and on. Here is the web site. http://www.dodge.com/bodybuilder/2004/docs/an/dts.pdf
The 2004 Dodge Dakota has a maximum rear axle capacity weight of only 3,850 LBS. This does not allow you enough axle capacity to pull a 5er even in the 1/2 ton series that some manufactures are producing.
For example take the 26SAB Cougar (1/2 ton tow-able), this has a gross vehicle weight of 9,990 LBS and the pin weight that the rear axle will see is 1,998 LBS. This weight plus the hitch, fuel and two passengers in your truck will overload the rear axle and tires capacity. Sorry if you want to pull a 5er look at a 3/4 ton or larger model of truck first.