The first thing to remember is that if the vehicle sits still for to long the suspension will settle to the bump stops, not good for access once the box is repaired.
My advise would be to get the Rangey as high as possible, use car ramps under all the wheels then use wooden chocks through the ramps to stop the motor rolling off the ramps or have one pair facing the opposite direction so the stops hold the wheels (remember no transmission, no hand brake). If you only have one set of ramps use them under the rear wheels. Now raise the suspension as high as possible and place wooden blocks between the bump stops and the chassis then lower, you now have a safe vehicle to work on.
I'd drain all the transmission oils then remove the transfer case from the transmission before trying to pull the auto trans, pull the auto box with the torque converter as a complete unit. You will have to replace it like this due to possible damage caused the transmission input drive/oil pump if you don't.
A 4x4 style transmission assembly shape does not make it easy to control plus they can be very very heavy once you are underneath them. I'd also recommend that you use at the very least a trolley jack to try to support the weight of the box, plus 2 other people to help control the box and jack. A transmission can easily break an arm or hand if not controlled (if you can hire/find someone with a floor transmission jack, beg or pay to use it).
Pulling a transmission on these vehicles is not fun from underneath without a 4 post ramp, but can be be done with great care and consideration, before unbolting anything, ask yourself what could happen if you get it wrong, it will hurt you.
Remember to control/support the engine while removing the trans as you have also removed the rear mounting for the engine.
