I disagree with getting an LT rated tire for your uses, whether E or C rated. The XL rated stock Dunlops, and any of the tires you are considering in a P (or iso-metric ) rating, can handle the full 8300lb towing capacity of the truck. LT tires are required on 3/4 ton pickups but even half ton pickups, with 10,000+ towing capacity, come on P rated tires. You do not need LT rated tires for towing on a stock rig. LT tires will mean a rougher ride, worse braking, longer stopping distances, and worse mileage.
Your description of your off road uses sound like something that a P rated tire can easily handle. If you’re taking on sharp rocks and difficult trails then LT tires would be warranted. For mild trails and dirt or gravel roads a P or XL rated Defender is fine.