lifting small boulders?

[rusty quoin]

4. If your lawn tractor cannot handle them, I don't know what can do without help.

You cannot pick them up, but you can roll each one off the pallet with a bar or shovel.

I guess you can use a winch and ropes. Try to roll each Boulder onto a net, or even a tarp, and crank it up the hill strategically. Even this way would be better with help.

I assume what you say will mess up the plastic cart, but there might be smaller stone that the cart can handle. I admire your determination.