I believe our truck with the 18.5 ft body weighed in at right around 21K. Add 1100 lb of water, 1388 lb of diesel and a full stock of recovery equipment, tools and all the things you need I would expect to be around 25-26K max. I've been on some soft sand and on some somewhat rough terrain. Aired down to around 60 psi it did well in moderately loose sand. Keep in mind the tires are designed to operate at 110 psi max. As far as traction goes we had no trouble getting up a fairly loose steep grade in 4wd lo. It has a locking transfer case and I believe it locks front and rear drive axles once engaged. With the locking rear we had plenty of traction. I can see where a front locking diff would be desirable and I'm sure its available but I didn't see the need. I did opt for manual hubs and I think GXV is putting them on all the Kenworth trucks standard now. The first one didn't have them. I'll double check but I really believe the massive divorced transfer case that is going in the Kenworth isn't a "center diff" but a true locking transfer case.