Well, it all depends on how structurally sound the body tub is to begin with. I have pulled the ass end of the body of my car off the frame with a engine hoist, by chaining it through the loop the trunk latches to. I left the front 2 bolts installed as all I wanted to do was de-rust the frame back by the wheels, and replace the engine mounts and swap the fuel line. Now, I suppose you could do a variation of this by using a technique I had seen pictured in a book. They used 4 55 gallon steel drums, and some wood to put the tub of a 1966 GTO up high enough to roll the frame out from under it. You could use the technique I outlined to pull up the rear and put a beam through the wheel wells, and then lift the front up using a jack with wood under the floor, or another stable lifting point at the front of the car and the hoist or a chain fall. If you used a chain fall, you could use a chain connecting the lower corners somehow and then lift at the middle of the chain. Just remember: This is all just theory on my part as I have no idea how bad your car is, nor have I completely removed the body from the frame of my car. Now if you wanted to just lift it one side at a time, you could remove all the body bolts from one side, and lift the body from the frame a few inches to inspect one side at a time. Just remember that doing this does tend to open a Pandora's Box of issues, and you will need new body mount bushings after pulling it apart. The hardware will probably disintegrate, or be otherwise unusable. Mine was, and the car was 11 years old (this is 1996 or 97), rust free and from the south. Yours could need captive nut repairs as the cages may be rotted and will not hold their nuts. You could also twist the body tub, or crack the windshield if the car has lost structural integrity. To prevent this, you would need to brace the body by welding in steel supports to keep it square. A neighbor and I did this when we pulled the body off the pan of a 1966 VW Type 1 with extensive rust.
1985 Cutlass Supreme Brougham (ex pizza delivery beater with 240,000 miles):
355 Chevy- 9.5:1 compression, Comp XE 262 cam, World S/R Torquer heads with 2.02's, Edelbrock Performer, 800CFM Q jet, Camaro ram air system,Edelbrock headers, Comp Magnum roller tip rockers,TH 200 4R, 3.23 rear, aluminum hood, IROC steering box, poly bushings, Eibach springs, etc. Cutlass build thread here: viewtopic.php?t=4982
Also: The Thing That Won't Die-1998 Nissan Frontier, 340,000 miles of pizza delivery.