I put 4 degrees "minimum" in every solid axle vehicle I ever work on. With some very large tire vehicles, less caster is easier on the steering when the vehicle is stationary, but on a Dodge with around 35" tires I say go with closer to 5 degrees.
Here's the thing... .
Caster, IMO, is one of the only specs that you can do yourself on a dodge that is up to what YOU want. It isn't about the "degree" but rather the feel and handling you get. Wider rims, different backspacing, and larger and wider tires all make a difference in "feel" so it's very hard to say what is optimal for ALL dodges, but stock caster is way too low a number.
If there was anything to worry about I would say take your truck into a shop to do this, but theres not... . If you can handle loosening a bolt and tapping the cam a half inch, you can do this yourself. The numbers REALLY don't matter as you cant go TOO far with the dodge cams, it's up to what YOU like...
Don... .