When I've removed bodies in past, I've not had a crane either. What I did was to jack the truck up high enough that I can roll the chassis out. Because Jack stands don't usually go that high, I made wooden stands that could be slid in easily, but also used cribbing that is more stable.
Once you have it jacked and stablized so you feel comfortable that it's not going to fall, then unbolt the chassis, slowly lowering it a fraction of an inch till you're sure it is fully detached and clear.
When you have the chassis on the ground. you then build up the cribbing, placing a beam under the body at the same locations as the body mounts are located. block and shim to those points.
finally because you have "bridged" the chassis, you can roll it out.
Just keep in mind, you don't want to twist or bend your body, so keep an eye out that everything is plumb, level, etc.
I little time cosuming, but safe and effective.
