Of course I don't know what equipment you already have, but here are a couple of suggestions.
First, if you have a fairly sound truck, you might get something like one of these.
http://www.northerntool.com/shop/tools/category_material-handling+hoists-lifts-cranes+truck-cranes
I had an older, smaller version in my old truck, and it worked well, though it was awkward. These are much better.
I built a trailer for a friend's wife a few years back. She was running a place that sold concrete fountains and stuff. I used one of those cranes. The ultra-tow number 52514. I did some mods to it.
I replaced the winch with a brake-winch. I
Highly recommend doing that on any hand winch device you wind up with.
If you have never used one, they are great. They are always locked. To winch something up, you simply turn the handle normally. To lower something, you turn the handle backwards.
No locks to release, and if you let go of the handle, it stops right there, even if you are lowering something.
Here is what they look like.
http://www.northerntool.com/shop/tools/NTESearch?storeId=6970&ipp=48&Ntt=brake+winch
The trailer, was a Northern trailer, which I heavily modified.
Pretty sure it was this one.
http://www.northerntool.com/shop/tools/product_200612543_200612543
Considering who was going to be using it, I found the stamped sheet metal frame to be a little skimpy. I replaced most of it with thick wall square tubing.
I welded a 1/2 inch thick steel plate on the front and back of the trailer. Drilled and tapped holes in them in the mounting pattern of the crane. So the crane could be mounted front or rear and easily moved.
I attached a drop down foot brace to the lower, non-rotating, part of the crane. Replaced the front trailer hitch with a pin type hitch to go on the golf cart she used.
You can see it in use in the first pic. The eye bolt with the hitch pin through it was temporary just to get it to her. Later I replaced that with a heavy chromed wheel with a bolt.
To use it, you pulled the trailer up next to the weight. Loosened the screw, and the leg dropped to the ground. Tighten the screw, and the leg was locked. The front mounting plate had an eye bolt screwed into it to hook the crane hook to to keep it from flopping around.
After locking the leg, you unhooked the hook, swung the crane around and picked up the load. The front of the trailer was supported by the golf cart, and the back end by the leg.
That way, it did not rock and move on the springs while loading. Then you set the load on the trailer, loosened the screw, raised the leg with the small handle on top, and locked it back in the raised position.
With the trailer fairly short, and hooked to a golf cart, the whole thing was very maneuverable.
If you have a pickup with a solid frame, mounting one of the cranes in the bed with a plate attached to the frame would be the way to go. Otherwise, one of those cranes on a small trailer would work. Either way, add the brake winch.
I mounted mine on the right rear corner of the bed. It was shorter than Northern's, and could collapse down to lay on top of the wheel well under the edge of the top of the bed. Got it from JC Whitney, back in 1979. Not sure they make them anymore.
