If you have the Off-Road package, which comes with the lower gears, then getting the rest of the parts that make up the tow package is a lot easier with the exception of the trans temp gauge.
The parts are...
You have the same cooling equipment, the Off-Road package has the same gears as the tow package and that is what gives you the brunt of the tow capacity. The tow package has a bigger battery, but that's not a huge deal and won't increase your tow capacity any.
The trans temp gauge also comes with the tow package but isn't as easy to install since you need to replace the gauge cluster. You'd be better off adding an aftermarket gauge.
And you can even install a nice aftermarket trans temp gauge. It'll look good on a pillar mounted gauge cluster. You have the means to upgrade easily if you choose so. Some aftermarket gauge clusters come with this feature if the wiring/plumbing is existing or added.