is there anything that can increase the turning radius on my truck?

Yep. Don't turn the steering wheel as far as you normally would.

Actually, you want to DECREASE the turning radius. Easiest way is to use smaller circumference tires on the front axle. It won't reduce the turning radius by much. There's nothing else you can do without major machining because you'll have to shorten some of steering linkage components, and lengthen some others.

If you look at a Styrofoam coffee cup, you'll notice that the top of the cup has a larger circumference than the base of the cup. Lay it on its side and roll the cup; you'll notice the turning radius of the base is tighter than that of the top.

Increasing the turn radius would mean that you would need even MORE room to make a turn. If you want to make a tighter turn, you would DECREASE the turn radius.

Oh... BTW. I drive a Silverado CREW CAB long bed... It's about 2 feet longer than your truck.

Not really, because the turn radius is a function of how far you can turn the wheels without having them rub the inside of the wheel wells and the suspension equipment. And, this is determined by the design of the vehicle (how much the designers have allowed the wheels to turn from lock to lock).

If you wish to INCREASE the radius just don't turn the wheel so hard.