Look here and you can see what I did. I had a load of gravel dumped. WHat I dont use on the pond I'll save for my driveway. With a helper, you're in high cotton! I did all mine myself so have a couple tips to maximize efficiency, or at least how I did it.
In the first pic, you can see the little plywood funnel I made to fill the block holes. On one end there is a "tail" out of a 2x4 that sticks down into the block to keep it from falling over. I made it so I could fill both cells of a block at once. That was a big help no matter where the concrete comes from.
In the third pic, you can see my old wheelbarrow which had broken its last handle. I used the tub as a staging area. When concrete was mixed I would dump it in there then start putting another batch in the mixer. While the mixer was mixing I was filling the blocks. I used 2.5-3 gallon buckets to carry.
It takes a bit longer to mix when starting from scratch so worked well to have a system going. When mixing, you'll want to put all your gravel in first , then part of sand, then cement, then rest of sand. Dont put the sand or cement in first as it will stick to the bottom of the mixer.
Oops, after I typed all this, I just remembered you used to do this for a living. Sorry.