Hi @ironbark,
If you are already on the Dewalt system, then you would want to look at a higher-end, brushless drill such as this DeWALT 18V XR Premium 3 Speed Hammer Drill Driver.
It will have much higher torque than entry-level models, and it has an Anti-Rotation System for enhanced control in bind-up situations. If the drill senses that the bit has bound and the tool is starting to rotate unexpectedly, it immediately cuts power to the motor. This stops the rotation, protecting the user from a kickback.
Ultimately, drilling into the ground will still be heavy work, and there is always going to be potential for kickback. For this application, using the side handle is a must. This will give you even more control over the tool in the event of kickback.
Have a look at the tools listing on Dewalt's website here -18V XR Premium Brushless Hammer Drill Driver.
I would also consider grabbing a high-amp battery such as this DeWALT 18V 8.0Ah Power Tool Battery if you didn't already have one. You will get much more power and runtime from a larger battery, and from experience, jobs with high torque requirements go a lot easier with a bigger battery.
Let me know what you think and if you have any further questions, please don't hesitate to ask.
Jacob
