Here are the first two bins filled. It took about a half truck load of mushroom soil to do what you see here. I expect to pick up another yard before I'm finished. There was no easy way to do this but shovel in and shovel out. Luckily mushroom compost is light and spongy, not like topsoil or even garden compost. But I was tired after this and had to take a break.
Notice the outlet tube from the sub heating system. It blows right across the entry door.