By the way, it would be cool if more people would put information about their setup in their signature. This was common in the 80s forum, so it's easy to see what people have without having to search.
I've been offroading on a couple of easy to moderate trails in Big Bear, Borrego Springs, and Joshua Tree. I have the OEM rear airbags and OEM rear springs. I'm just using a spacer under the rear air bags to level the rear with the front 6112 coilovers that lifted about 2.5" in the front.
The things that I would worry offroading with a stock gx470 is the clearance of the running boards and highway tires that it comes in stock form. So, I would remove the running boards and put bigger tires. I would go offroading on easy trails just to try it out.
I always worry about damaging the rocker panel, so I immediatelly think of a 2" lift, 33" tires, and rock sliders. This has served me well on the gx470 and I haven't really hit anything bad in the easy/moderate trails that I've been on, but sometimes you come close to hiting the side of a canyon or landing on a high rock.
Anyways, as others have mentioned, the GX470 is offroad capable as it is. Don't make the mistake of spending all your time and money getting it offroad ready and you never get out.