You'd need springs and bags in my opinion. That's a lot of liquid load all wallowing right over the rear axle. That's a different scenario than having 2300lbs spread over all 4 axles.
I would do it with the following conditions:
1. Replace coils and add bags both- the more roll control you have, the better.
2. Even that short distance is going to play hell on your brakes.
3. Remember with that weight all right over the axle, you are one big bump away from separating your axle tube, bending a shaft, snapping lugs, bending or breaking a coil mount, or cracking a rim- worst case scenario bending your frame.
My thoughts on this come with no warranty, and you should do what you're comfortable doing. Looking at face value we're only talking 600lbs extra. That's an extra 300lbs per wheel. But in the grand scheme of it, we're looking at 2300lbs sitting right on that rear axle. If you had an idea what your rear axle weight was empty we could make a better decision. I'd hate to see you bend your frame or snap something in a pothole :/
EDIT: I am not wanting to be a hypocrite. I run overweight a lot. The beefier springs, tires, shocks help it handle the load like a champ, but that is spread out over four axles not two.
