The Rebel is already pretty capable off road, with a 5.7l Hemi V8, 3.92 rear and LSD, 33" tires, and a BW 44-45 locking center diff, so the primary focus in terms of capability for me is tires. I upgraded the stock Toyo Open Country A/T tires with a set of 305/70-17 Nitto Ridge Grapplers. These tires come out to be a little more than an inch larger in diameter than the Toyos, as well as about 3/4" wider. They're also something of a hybrid between A/T and M/T tires, so they're very capable off road, but also pretty well-mannered on the road. Along with these tires, I upgraded to a set of Fuel Anza wheels - 17x 8.5" with a -6mm offset. The end result is about 1/2" more tire clearance on the inside, and the tires sticking out 1-1/2"+ which fills the fenders very nicely, without sticking out past the tops of the fenders. Pretty much a perfect fit (although I did order a set of 1/4" spacers for the rear, as I think the rears could come out a bit more to better match the profile of the fronts).
So far, on the road, these tires have been great. Their road manners are very similar to the OE Toyos, which is to say very low noise and decent dry grip for this type of tire. They haven't seen rain or snow yet, but according to reviews, they have great wet traction for such an aggressive tread, and snow traction is excellent (much better than the OE Toyos). I'll be interested to see how good they do on the trails at AOAA at the end of the month!
Here's the truck as it currently sits....
And here it was stock: