I recently had a stump about 40" in diameter ground up. I had to remove about 4 wheelbarrow loads of wood chips afterwards to get it level. I put some grass seed and some Miracle Grow garden soil on it.
I did the same to another area a few springs ago and by mid summer you couldn't tell where it was.
Also, I've placed half of a 55 gallon barrel around a stump, poured in about 5" of charcoal and lit it up. It takes 4 or 5 applications, but it will eventually burn it down to grind level.
problem with leveling it in the beginning is that the stump will continue to rot way down, you'll be adding top soil on an almost yearly basis. Always try to leave a small mound and it will eventually level. Atleast that has been my experience.
