There is a bark place down the road that sells mushroom compost and steer
compost. Is this stuff good for the garden? Can I use it like compost and
heap it on the ground around plants and trees?

It is aged, you can tell by looking at it, but there is no telling how long
it was aged. It has a fairly pleasant odor (for manure, that is) which would
indicate some aging. I think I'll go sparingly just in case...hate to fry my
plants with hot manure.