You didn't mention year model. A lot of companies such as Rough Country make leveling kits that allow you to go up a size or 2 on tires. Most of the leveling kits plus the bigger tire will raise your floor board about 3 inches. Again, not sure what is offered for your specific truck.
The leveling kit under my Silverado is plenty. Otherwise, I'd be wearing out the edge of the seat. And the truck is plenty tall enough for clearance going off road...the taller tires still have room for moderate suspension flex.